100

#  TESS Cycle 2 observations of roAp stars with 2-min cadence data

D. L. Holdsworth,1,2 M. S. Cunha,3 M. Lares-Martiz,4 D. W. Kurtz,5,1 V.
Antoci, 6 S. Barceló Forteza,7<EMAIL_ADDRESS>P. De Cat,8 A.
Derekas,9,10,11 C. Kayhan,12 D. Ozuyar,13 M. Skarka,14,15 D. R. Hey,16 F.
Shi,17,18 D. M. Bowman,19,20 O. Kobzar,21 A. Ayala Gómez,22 Zs. Bognár,23 D.
L. Buzasi,24 M. Ebadi,25 L. Fox-Machado,26 A. García Hernández,27 H.
Ghasemi,28 J. A. Guzik,29 R. Handberg,30 G. Handler,31 A. Hasanzadeh,32 R.
Jayaraman,33 V. Khalack,21 O. Kochukhov,34 C. C. Lovekin,35 P.
Mikołajczyk,36,37 D. Mkrtichian,38 S. J. Murphy,39 E. Niemczura,36 B. G.
Olafsson,1 J. Pascual-Granado,40 E. Paunzen,41 N. Posiłek,36 A. Ramón-
Ballesta,42 H. Safari,43 A. Samadi-Ghadim,44 B. Smalley,45 Á. Sódor,23 I.
Stateva,46 J. C. Suárez,47 R. Szabó,23,48 T. Wu,49,50,51,52,53,54 E. Ziaali,55
W. Zong56,57 and S. Seager58,59,60
Author affiliations shown in Appendix A

###### Abstract

We present the results of a systematic search of the Transiting Exoplanet
Survey Satellite (TESS) 2-min cadence data for new rapidly oscillating Ap
(roAp) stars observed during the Cycle 2 phase of its mission. We find seven
new roAp stars previously unreported as such and present the analysis of a
further 25 roAp stars that are already known. Three of the new stars show
multiperiodic pulsations, while all new members are rotationally variable
stars, leading to almost 70 per cent (22) of the roAp stars presented being
$\alpha^{2}\,$CVn-type variable stars. We show that targeted observations of
known chemically peculiar stars are likely to overlook many new roAp stars,
and demonstrate that multi-epoch observations are necessary to see pulsational
behaviour changes. We find a lack of roAp stars close to the blue edge of the
theoretical roAp instability strip, and reaffirm that mode instability is
observed more frequently with precise, space-based observations. In addition
to the Cycle 2 observations, we analyse TESS data for all known roAp stars.
This amounts to 18 further roAp stars observed by TESS. Finally, we list six
known roAp stars that TESS is yet to observe. We deduce that the incidence of
roAp stars amongst the Ap star population is just 5.5 per cent, raising
fundamental questions about the conditions required to excite pulsations in Ap
stars. This work, coupled with our previous work on roAp stars in Cycle 1
observations, presents the most comprehensive, homogeneous study of the roAp
stars in the TESS nominal mission, with a collection of 112 confirmed roAp
stars in total.

###### keywords:

asteroseismology – stars: chemically peculiar – stars: oscillations –
techniques: photometric – stars: variables – stars: individual

††pubyear: 2024††pagerange: TESS Cycle 2 observations of roAp stars with 2-min
cadence data–78

##  1 Introduction

The Transiting Exoplanet Survey Satellite (TESS; Ricker et al., 2015) is
providing a rich photometric data set for millions of stars in most regions of
the sky. While the primary mission focus is on the detection of exoplanet
transits, the acquired data are well suited for studies of stellar
variability. TESS observes the sky in strips of 24${}^{\circ}\times
96^{\circ}$ for about 27 d each, referred to as sectors. TESS is observing in
1-year cycles, each composed of 13 sectors. For the nominal mission comprising
Cycles 1 & 2, TESS recorded data in two cadences: 30 min for the Full Frame
Images (FFIs) and 2 min for a selection of $\sim$20 000 stars per sector.
These 2-min cadence data provide a data set with which it is possible to
perform a homogeneous search for high-frequency stellar variability. We have
previously exploited this capability to search for high-frequency pulsations
in the chemically peculiar Ap stars (Holdsworth et al., 2021, hereafter Paper
I) in the Cycle 1 data. Here we extend this study to encompass the 2-min Cycle
2 observations.

The rapidly oscillating Ap (roAp) stars are a rare subset of the chemically
peculiar, magnetic, Ap stars (Kurtz, 1982). To date there are of the order 100
known in the literature (see e.g., Smalley et al., 2015; Joshi et al., 2016;
Cunha et al., 2019; Holdsworth et al., 2021; Alecian & Stift, 2021, for
catalogues and lists), discovered through targeted high-speed ground-based
photometry and spectroscopy (e.g., Martinez et al., 1991; Paunzen et al.,
2018; Freyhammer et al., 2008; Kochukhov et al., 2013) and space-based survey
data (e.g., Gruberbauer et al., 2011; Balona et al., 2011b; Hey et al., 2019;
Cunha et al., 2019).

The broader population of Ap stars is characterised by strong, global,
magnetic fields (Mathys, 2017) that suppress near-surface convection in the
stellar atmosphere (Michaud et al., 1981; LeBlanc et al., 2009; Alecian &
Stift, 2010), leading to gravitational settling of some light elements and
radiative levitation of metals like P, Si, Ti, Fe, Cr and Mn (Khalack &
Poitras, 2015; LeBlanc et al., 2015; Khalack et al., 2017; Ndiaye et al.,
2018; Folsom et al., 2022) and rare earth elements like Pr, Nd, Eu and Y,
which can reach atmospheric abundances of a million times that of the Sun
(e.g., Lüftinger et al., 2010; Castelli et al., 2017; Khalack, 2018). These
levitated chemical elements create persistent atmospheric anomalies that may
be stable for at least a century (e.g., Bychkov et al., 2016). These
anomalies, i.e. chemical spots, modulate the observed flux, enabling the
accurate determination of the stellar rotation period. Rotationally variable
Ap stars are known as $\alpha^{2}$ CVn stars.

The roAp stars are characterised by high overtone ($n\gtrsim 15$), low degree
($\ell\lesssim 3$) pressure (p) mode pulsations with frequencies in the range
$0.7-3.6$ mHz ($60-310$ d -1; $P=4.7-23.6$ min). In many non-magnetic stars,
the pulsation axis is aligned with the rotation axis as this is the axis of
maximum deformation from spherical symmetry. In the roAp stars, however, the
pulsation axis is closely aligned with the magnetic axis (e.g., Kochukhov,
2004) which in turn is inclined to the rotation axis. Such a geometry means
the pulsations are viewed from varying aspects as the star rotates, leading to
the oblique pulsator model (e.g., Kurtz, 1982; Saio & Gautschy, 2004), where
the mode amplitude and phase appear modulated over the stellar rotation
period. In a Fourier spectrum of a light curve, this results in a multiplet
with $2\ell+1$ components for a non-distorted mode, with the components split
from the central mode frequency by exactly the stellar rotation frequency.
With a geometrically distorted mode, the multiplet shows more components
(e.g., Holdsworth et al., 2016) and the pulsation amplitude never reaches zero
as a node crosses the line of sight. The distortion arises from the magnetic
field’s interaction with the pulsation mode’s eigenfunction, which then
requires higher order spherical harmonics to describe the mode (see Kurtz,
1992; Holdsworth et al., 2018a; Shi et al., 2021, and references therein for
discussions).

The driving mechanism for the pulsations in these stars is still uncertain. In
many cases, theoretical models can recreate the observations by employing the
opacity ($\kappa$) mechanism acting in the hydrogen ionisation layers in
regions of the star where the magnetic field suppresses convection (Balmforth
et al., 2001). However, this method cannot explain all of the observed
frequencies, especially those at very high frequency, where instead it is
suggested that turbulent pressure plays a role in the mode excitation (Cunha
et al., 2013).

The most promising stars for asteroseismic insight are those that show
multiperiodic variability. In a non-magnetic star, the high frequency
pulsations occur in the asymptotic regime, forming a series of alternating odd
and even degree modes (Shibahashi, 1979; Tassoul, 1980) that allow the use of
asteroseismic techniques to constrain the stellar properties, e.g., Deal et
al. (2021). However, the situation is complicated in some roAp stars as the
pulsations become magneto-acoustic in the outer layers of the star, and their
frequencies suffer from magnetic perturbation (Cunha & Gough, 2000; Cunha,
2006; Saio & Gautschy, 2004). Detecting such phenomena in the roAp stars helps
to drive forward the theoretical modelling of the class, and provide the
opportunity to fully understand roAp stars.

Recently, the validity of the roAp class was questioned by Balona (2022), who
suggested that all roAp stars are just $\delta$ Sct stars. However, this is
clearly not the case. While there is overlap in the frequency regime where
both $\delta$ Sct pulsations and roAp pulsations are found (in different
stars), the roAp stars are distinct from the $\delta$ Sct stars given their Ap
chemical peculiarities, oblique pulsations, and strong, stable, magnetic
fields. There are some cases where roAp stars do show low-frequency $\delta$
Sct pulsations (e.g., Murphy et al., 2020), and new results where a magnetic
field has been confirmed in an Ap star potentially showing $\delta$ Sct
pulsations (e.g., Neiner & Lampens, 2015; Escorza et al., 2016; Hubrig et al.,
2023). While the former work rules out a companion to the roAp star, they
place limits on the magnetic field strength that can suppress low-overtone
pulsations. The latter work cautions that an undetected companion to the Ap
star may provide the $\delta$ Sct pulsations and that their derived field
strength is close to the limit provided by Murphy et al. (2020), thus no
certain conclusions can be drawn on the presence of $\delta$ Sct modes in a
magnetic Ap star. The suggestion, therefore, that the roAp classification
should be abandoned is not useful and is rejected. It is only with careful
study and interpretation of valid evidence that stars should be admitted to
the roAp class of pulsating variable.

##  2 Data sample and search strategy

To present a homogeneous sample of roAp stars observed by TESS during its
nominal mission, we followed the same procedure as in Paper I. One team, Team
1, took the 2-min target list for each sector of observations from
TESS111https://tess.mit.edu/observations/target-lists/ which consisted of 20
000 stars per sector. These lists were then crossmatched with version 8 of the
TESS Input Catalogue (TIC; Stassun et al., 2019) with an 8 arcsec radius,
giving us access to the secondary information in the TIC to refine our list of
targets. Using only the $T_{\rm eff}$ parameter, we selected stars with
temperatures of 6000 K or greater (including stars with a ‘null’ value). This
amounted to about 7500 stars per sector, with 93 163 light curves in total,
corresponding to 36 209 unique stars (with 15 675 stars observed in more than
one sector). The light curves for each star in all available sectors were
downloaded from the Mikulski Archive for Space Telescopes (MAST) server. These
data have been processed with the Science Processing Operations Center (SPOC)
pipeline (Jenkins et al., 2016), which are the most suitable data for the
investigation of stellar variability (Skarka et al., 2022). In the following
we used the Pre-search Data Conditioning Simple Aperture Photometry (PDC_SAP)
data unless otherwise stated.

Initially, two independent analysis techniques were implemented for the search
of pulsational variability. For one team, Team 1, each individual light curve
was automatically prewhitened of all frequencies up to 0.23 mHz (20 d -1) to
an amplitude limit of the approximate noise level between $2.3-3.3$ mHz
($200-300$ d -1) to remove instrumental artefacts and any low-frequency signal
whose window function affects the noise at high frequency. If multiple sectors
for a target were available, the prewhitened sectors were then combined. An
amplitude spectrum of the light curve was calculated to the Nyquist frequency
of 4.2 mHz (360 d -1), which also included a calculation of the false alarm
probability (FAP).

From these amplitude spectra, we selected stars that showed peaks with
frequencies $>0.52$ mHz ($>45$ d -1) and a corresponding FAP of $<0.1$. The
amplitude spectra of these stars were then plotted for visual inspection. This
totalled 6713 stars, of which 2125 stars have multi-sector observations.

A second team, Team 2, used a complementary method which calculated the
skewness of the amplitude spectrum (Murphy et al., 2019) of the MAST PDC_SAP
data above 0.46 mHz (40 d -1). Where multiple sectors of data were available,
they were combined to a single light curve. If the skewness was greater than
5, then all peaks in the amplitude spectrum with FAP values below 0.05 were
extracted and the star flagged as variable for later human inspection. This
method produced a total of 189 variable star candidates.

These two lists were then combined to produce a master list. An initial pass
was made with the echo code (described in Antoci et al., 2019) to flag
possible false positive detections with human inspection of all produced
outputs (light curves, Fourier transform plots and detected peaks). A
detection was determined to be false positive if the signal-to-noise ratio
(S/N) of the high-frequency signal was below 4.0; if there was obvious
contamination from a low-frequency harmonic series; or if the amplitude
spectrum displayed obvious characteristics of either $\delta$ Sct stars (with
many modes in the $\approx 0.2-1.0$ mHz range, e.g., Bowman & Kurtz 2018),
sdBV stars (stars with pulsations in low and high-frequency ranges) or
pulsating white dwarfs (modes with amplitudes significantly greater than those
known in roAp stars). The final sample consisted of 163 stars.

Further, we solicited input from the TESS Asteroseismic Science Consortium
(TASC) Working Group 4 (WG4; AF-stars). This ensured that our study was not
biased by the two methodologies outlined above. Contributions from the WG4 are
as follows:

  * •

Team A used the TESS Input Catalog (Stassun et al., 2018) and Gaia DR2 Catalog
(Andrae et al., 2018) to look for all stars with SIMBAD spectral types between
B8 and F2 (stars with no classification were retained) in the Northern
ecliptic hemisphere with effective temperatures between 6000 K and 10 000 K,
luminosity between 5 and 100 L⊙ and a contamination ratio lower than 0.01.
Using the interpolation and frequency analysis routine of Barceló Forteza et
al. (2015), the team found 121 candidates where the highest amplitude peak was
in the frequency range $0.7-4.0$ mHz and without lower frequency modes in
order to avoid the $\delta$ Sct star pulsation regime (e.g., Aerts et al.,
2010; Barceló Forteza et al., 2020, and references therein).

  * •

Team B used the Cycle 2 data to search for targets with a magnitude brighter
than $T=10$ mag and an effective temperature of >6000 K. The resultant SAP
light curves were used to derive rotation periods which were then removed from
the data before pulsation frequencies were searched for using the Lomb-Scargle
method. This procedure resulted in 9 candidates.

  * •

Team C considered stars located close to the northern ecliptic pole (within
$15^{\circ}$), which were brighter than $T=11$ mag, with temperatures in the
range $6000<T_{\rm eff}<10\,000$ K (Skarka et al., 2022). Frequency spectra,
in the range $0-4.2$ mHz ($0-360$ d -1) were created from the PDC_SAP data
obtained from the MAST and searched for significant peaks. In total, 1600
stars showed peaks in the frequency range $0.9-4.2$ mHz ($80-360$ d -1) with a
S/N $>4$. However, only stars with peaks with S/N $>5$ were selected as good
candidates (8 stars).

  * •

Team D provided 55 roAp candidates using the TESS-Ap procedure (Khalack et
al., 2021). A search for pulsations in the frequency range $1.2-4.2$ mHz
($100-360$ d -1) was conducted to limit the inclusion of $\delta$ Sct stars.
Only stars in the effective temperature range $6000-10\,000$ K were
considered. Peaks were considered real if the S/N $>4$. After the automatic
selection, manual inspection was conducted to reject false positives.

  * •

Team E used the TIC to select all stars in the temperature range
$6000-10\,000$ K for which 2-min cadence data were available. The light curves
were downloaded from the MAST server, from which the PDC_SAP flux data were
extracted. Only the first $\sim 12.5$ d of data were selected to avoid the
central downlink gap. Any other gaps are much smaller in size and a piecewise
cubic Hermite polynomial was used to fill them with interpolated data at 2-min
cadence. No detrending of low-frequency variability was performed. The
sampling intervals were then regularised in order to obtain an evenly sampled
time series that was analysed using an FFT to calculate the amplitude spectrum
to the Nyquist frequency. A star is selected to be variable when a local
maximum is found in the amplitude spectrum to have a S/N $>5$ and a frequency
greater than 0.5 mHz ($\sim 43$ d -1). This procedure returned 1241 stars
which were vetted by eye to produce a final list of 1134 variable candidates.

  * •

Finally, 8 additional targets were submitted from members of WG4 where
individuals had made private note of stars of interest.

All of these inputs from WG4 members were cross-checked with the results from
Team 1 and Team 2 to avoid duplication. Team 1 then re-vetted all unique
submissions to reject obvious non-roAp variable stars to produce a final
sample list of 116 stars.This final sample was redistributed amongst the
members of the TASC WG4 for detailed analysis to confirm the presence of a
positive roAp detection, and to extract rotation periods from the light
curves.

This process identified seven new roAp stars previously unreported as such in
the literature (Sec. 4.1) and nine roAp stars discovered through TESS
observations (Sec. 4.2). There were also positive detections of pulsations in
12 roAp stars known prior to the launch of TESS (Sec. 4.3), with four roAp
stars where TESS did not detect pulsational variability. These four stars were
originally identified in Kepler data which has a lower noise threshold than
the TESS data analysed here. Finally, we present seven roAp candidate stars
where the observational and archival data do not allow us to conclude with
certainty that the star is a true roAp star.

##  3 Spectroscopic observations

###  3.1 LAMOST data

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is a
4-m class telescope located at the Xinglong observatory (China) that is
operated and managed by the National Astronomical Observatories, Chinese
Academy of Sciences (Cui et al., 2012). Its scientific observations started in
October 2011. With its quasi-meridian transit configuration, it is possible to
observe northern stars with a declination above $\sim 10^{\circ}$ from two
hours before to two hours after meridian passage. This unique instrument
combines a large aperture (primary mirror of $5.72\,\rm{m}\times 4.40$ m;
secondary mirror of $6.67\,\rm{m}\times 6.05$ m) with a large field of view
($\sim$20 deg2). This circular field with a diameter of $5^{\circ}$ is
homogeneously covered with 4000 fibres, connected to 16 spectrographs with 250
fibres each. Currently, observations can be done either in the full optical
range ($3700-9000$ Å) in the low-resolution mode (LAMOST-LRS; $R\sim 1800$;
Zhao et al. 2012) or in a blue ($4950-5350$ Å) and red ($6300-6800$ Å)
wavelength range in the medium-resolution mode (LAMOST-MRS; $R\sim 7500$; Liu
et al. 2020). The LAMOST-LRS observations are single shot observations while
the LAMOST-MRS observations are done in two major groups of observations(for
further details see Liu et al., 2020; Zong et al., 2020). We checked the
LAMOST database and found data for six of our targets. Four targets had one
spectrum each (TIC 21024812, TIC 101624823, TIC 118247716, and TIC 467074220)
in LAMOST-LRS and two targets had groups of observations in LAMOST-MRS (TIC
26833276; 1 group of spectra, TIC 259017938; 6 groups of spectra). The
pipeline-reduced spectra (Luo et al., 2015) from data release 9 (DR9,
v1.0)222http://www.lamost.org/dr9/ were used to check if typical chemical
peculiarities expected for Ap stars can be identified in the data.

###  3.2 HERMES data

The High Efficiency and Resolution Mercator Echelle Spectrograph (HERMES;
Raskin et al. 2011) is mounted to the 1.2-m Mercator telescope at the
Observatorio del Roque de los Muchachos on La Palma in the Canary Islands,
Spain, and is operated by KU
Leuven333http://www.mercator.iac.es/instruments/hermes/. HERMES is a fibre-fed
prism-cross-dispersed echelle spectrograph with an effective wavelength
coverage between 3770 and 9000 Å, and in its standard high-resolution mode has
a spectral resolving power of $\sim$85 000. Reduced spectra are automatically
produced by an efficient Python pipeline, HermesDRS (v7.0), which includes
bias subtraction and flat fielding, as well as wavelength calibration using a
ThArNe spectrum, echelle order merging, and removal of cosmic rays. With its
Northern hemisphere observing window, as of semester 2018b, we embarked upon a
large programme (program 85; PI Bowman) to assemble high signal-to-noise (S/N
> 100), multi-epoch (minimally two epochs), high-resolution HERMES spectra of
all bright ($V\leq 10$ mag) Ap stars in the catalogue of Renson & Manfroid
(2009). The programme ran for two years and included more than 450 Ap stars in
total with $\delta>-30^{\circ}$. Thus the majority of observed Ap stars are
located in the Northern hemisphere ensuring complementarity with TESS Cycle 2
observations. Three stars presented in this work had HERMES data available.

###  3.3 Analysis

Data from both LAMOST and HERMES were normalised using the SUPPNet software
(Różański et al., 2022) with the default settings. Where we provide spectral
classifications, comparison is made between the observed spectrum and a set of
MK Standard stars. We aimed to find a match between the Balmer line profiles
and the non-peculiar metals to determine the broad spectral type, then note
those peculiar lines that are particularly abnormal in the observed spectrum.

The high resolution HERMES spectra were also analysed to provide estimates of
the effective temperature ($T_{\rm eff}$), surface gravity ($\log g$) and the
projected rotational velocity ($v\sin i$). Two separate teams carried out this
task, with their procedures below. We combine their results in the relevant
star section.

The first team used the software packages iSpec (Blanco-Cuaresma et al., 2014;
Blanco-Cuaresma, 2019) and the extended version of
handy444https://github.com/RozanskiT/HANDY (Różański, private communication).
Firstly, with iSpec, Balmer line profiles were fitted and an estimate of the
effective temperature with spectral synthesis was made using the synthe
(Kurucz, 1993; Sbordone et al., 2004) programme with the Castelli and Kurucz
model atmospheres (Castelli & Kurucz, 2003) and the VALD line list (Kupka et
al., 2011). This initial result was then used in handy-ext where synthetic
Balmer lines were calculated using the same underlying codes/inputs to
determine $\log g$, $T_{\rm eff}$ and $v\sin i$ via manually adjusting the
parameters until a good (visual) match with the Balmer lines was obtained.
Those parameters were then used to calculate a second, full, synthetic
spectrum in iSpec with which non-blended lines of Fe i and ii were found so
that $\log g$, $v\sin i$ and $T_{\rm eff}$ were re-calculated, via spectral
synthesis, with error estimates.

The second team used the ‘Balmer’ code, written in Python, based on the
spectrum synthesis method (Posiłek, private communication). The atmospheric
models and synthetic spectra were calculated with the atlas9/synthe software
(Kurucz, 2005). The determination of $T_{\rm eff}$ and $\log g$ was performed
using four Balmer lines (H$\alpha$, H$\beta$, H$\gamma$, H$\delta$). In the
case of temperatures lower than about 8500 K, the Balmer lines become
insensitive to $\log g$, and only the temperature was determined, with $\log
g$ assumed as 4.0 (cm s-2). Microturbulence was assumed to be $\xi=1$ km s-1.
An approximate value of $v\sin i$ was determined from the Mg 4481 Å line and
metal lines. Errors of estimated parameters were calculated as a weighted
median standard deviation of the fit to each line considered.

The results of these analyses are presented in the relevant subsections for
the three stars, TIC 21024812, TIC 435263600 and TIC 445493624.

##  4 Results

Here we present the results of our search and analysis of new and known roAp
stars in TESS Cycle 2 data. We provide an overview of the targets to be
discussed in Table 1 and divide this section, and the table, into subsections
addressing new discoveries reported in this work, previous discoveries reliant
on the TESS data, and TESS observations of known roAp stars. Finally, we
provide a list of candidate roAp stars where the currently available data do
not allow us to confirm the nature of these stars.

Table 1: Details of the stars analysed in this paper. The columns provide the TIC identifier and star name, the TIC v8.1 TESS magnitude, the spectral type as referenced in the stars discussion section, where ‘*’ denotes a classification derived in this work, the effective temperature as provided in the TIC (with typical errors up to 250 K), the sectors in which TESS observed the target in Cycle 2. The final three columns provide the stellar rotation period derived in this work, with a ‡ indicating a more precise period is presented in the literature and a † indicating this could be an orbital period, the pulsation frequency(ies) found in this work (note that sidelobes that arise from oblique pulsation are not listed), and the pulsation amplitude(s) seen in the TESS data. A‘**’ denotes rotation periods derived from rotationally split sidelobes. TIC | HD/TYC | TESS | Spectral | $T_{\rm eff}^{\rm TIC}$ | Sectors | $P_{\rm rot}$ | Pulsation frequency | Pulsation amplitude
---|---|---|---|---|---|---|---|---
| name | mag | type | (K) |  | (d) | (mHz) | (mmag)
New TESS roAp stars found in this work |  |  |
101624823 | 100598 | 8.18 | Ap Cr(SrEu)* | 6780 | 22 | $4.050\pm 0.001$ | $1.44176\pm 0.00001$ | $0.124\pm 0.006$
165052884 | 51561 | 8.81 | A5 | 6900 | 20 | $\sim 22$ | $2.176721\pm 0.000007$ | $0.243\pm 0.008$
233200244 | 161846 | 8.81 | A3 | 8220 | 14-19, 21-26 | $7.25002\pm 0.00006$ | $1.2614617\pm 0.0000016$ | $0.030\pm 0.003$
|  |  |  |  |  |  | $1.4390374\pm 0.0000005$ | $0.091\pm 0.003$
259017938 | 210684 | 7.15 | F0 | 7570 | 15,16 | $5.0226\pm 0.0005$ | $1.352116\pm 0.000006$ | $0.064\pm 0.003$
335457083 | 48409 | 8.20 | A3 | 7510 | 20 | $2.9139\pm 0.0001$ | $2.08819\pm 0.00002$ | $<0.015$
|  |  |  |  |  |  | $2.20575\pm 0.00003$ | $0.049\pm 0.006$
|  |  |  |  |  |  | $2.24835\pm 0.00003$ | $0.043\pm 0.006$
|  |  |  |  |  |  | $2.29691\pm 0.00005$ | $0.029\pm 0.006$
445493624 | 11948 | 7.7 | A5 SrEu(Cr)* | 8060 | 18 | $7.288\pm 0.002$ | $1.22522\pm 0.00003$ | $0.06\pm 0.01$
467074220 | 40142 | 7.55 | A8 SrCr(Eu)* | 7410 | 19 | $5.4195\pm 0.0004$ | $0.70462\pm 0.00006$ | $0.030\pm 0.007$
|  |  |  |  |  |  | $0.72476\pm 0.00003$ | $0.059\pm 0.007$
roAp stars previously discovered by TESS |  |  |
21024812 | 14522 | 8.59 | A8 SrEu(Cr)* | 8070 | 18 | $\sim 24$ | $1.10259\pm 0.00002$ | $0.096\pm 0.007$
25676603 | 2194-2347-1 | 8.50 | F0 SrEu | 6680 | 15 | >26 | $1.787321\pm 0.000027$ | $0.072\pm 0.008$
|  |  |  |  |  |  | $1.819500\pm 0.000002$ | $0.864\pm 0.008$
|  |  |  |  |  |  | $1.846724\pm 0.000008$ | $0.249\pm 0.008$
26833276 | 10682 | 7.51 | A3 | 6970 | 17 | >25 | $1.58317\pm 0.00002$ | $0.081\pm 0.005$
|  |  |  |  |  |  | $1.60714\pm 0.00003$ | $0.046\pm 0.005$
|  |  |  |  |  |  | $2.74058\pm 0.00004$ | $0.033\pm 0.005$
|  |  |  |  |  |  | $2.80741\pm 0.00004$ | $0.032\pm 0.005$
72392575 | 225578 | 8.83 | A Sr: | 7570 | 14 | $3.9016\pm 0.0008$ | $1.57343\pm 0.00003$ | $0.09\pm 0.01$
118247716 | 12519 | 8.13 | A7 SrEuCr* | 7060 | 17 | No signature | $1.94247\pm 0.00004$ | $0.040\pm 0.006$
|  |  |  |  |  |  | $1.97093\pm 0.00002$ | $0.098\pm 0.006$
|  |  |  |  |  |  | $2.03280\pm 0.00002$ | $0.070\pm 0.006$
120532285 | 213258 | 7.40 | Fp | 7210 | 16 | No signature | $2.171017\pm 0.000011$ | $0.095\pm 0.004$
|  |  |  |  |  |  | $2.198746\pm 0.000008$ | $0.128\pm 0.004$
|  |  |  |  |  |  | $2.226270\pm 0.000006$ | $0.159\pm 0.004$
129820552 | 2322-1440-1 | 9.90 | Ap | 7400 | 18 | $6.230\pm 0.002$ | $2.01305\pm 0.00002$ | $0.23\pm 0.01$
394860395 | 2666-85-1 | 9.23 |  | 7170 | 14 |  $22\pm 2$** | $1.18050\pm 0.00005$ | $0.09\pm 0.01$
435263600 | 218439 | 7.59 | A5 SrSi |  | 17, 24 | $3.0739\pm 0.0002$ | $1.097186\pm 0.000003$ | $0.063\pm 0.010$
|  |  |  |  |  |  | $1.097049\pm 0.000003$ | $0.059\pm 0.010$
|  |  |  |  |  |  | $1.117976\pm 0.000003$ | $0.039\pm 0.005$
|  |  |  |  |  |  | $1.124019\pm 0.000003$ | $0.037\pm 0.005$
Table 2: continued TIC | HD/KIC/TYC | TESS | Spectral | $T_{\rm eff}^{\rm TIC}$ | Sectors | $P_{\rm rot}$ | Pulsation frequency | Pulsation amplitude
---|---|---|---|---|---|---|---|---
| name | mag | type | (K) |  | (d) | (mHz) | (mmag)
Known roAp stars prior to TESS launch |  |  |  |
26418690 | K11296437 | 11.38 | A9 EuCr | 7010 | 14,15 | $7.11\pm 0.02$ | $1.409717\pm 0.000007$ | $0.32\pm 0.02$
26749633 | K11031749 | 12.39 | F1 SrCrEu | 7000 | 14,15 | No signature | No signal in TESS data | <0.18
27395746 | K11409673 | 12.58 | A9 SrEu | 7500 | 14,15 | No signature | No signal in TESS data | <0.15
77128654 | 97127 | 9.06 | F3 SrEu(Cr) | 6710 | 22 | No signature | $1.233855\pm 0.000004$ | $0.489\pm 0.009$
|  |  |  |  |  |  | $1.248661\pm 0.000031$ | $0.061\pm 0.009$
123231021 | K7582608 | 11.43 | A7 EuCr | 8400 | 14,26 | $19.805\pm 0.005^{\ddagger}$ | $2.1034011\pm 0.0000002$ | $1.32\pm 0.02$
158216369 | K7018170 | 12.89 | F2 (SrCr)Eu | 6950 | 14,26 | No signature | No signal in TESS data | <0.28
158271090 | K10195926 | 10.31 | F0 Sr | 7390 | 14,15,26 | $5.6845\pm 0.0002$ | $0.974579\pm 0.000002$ | $0.019\pm 0.009$
158275114 | K8677585 | 10.00 | A5 p | 7460 | 14,26 | No signature | $1.5853813\pm 0.0000009$ | $0.107\pm 0.009$
|  |  |  |  |  |  | $1.6217146\pm 0.0000019$ | $0.053\pm 0.009$
159392323 | 3547-2692-1 | 11.92 | F3 SrEuCr | 6390 | 15 | No signature | $1.47658\pm 0.00005$ | $0.21\pm 0.05$
|  |  |  |  |  |  | $1.49021\pm 0.00002$ | $0.66\pm 0.05$
|  |  |  |  |  |  | $1.49610\pm 0.00003$ | $0.34\pm 0.05$
169078762 | 225914 | 9.00 | A5 SrCrEu | 8100 | 14 | $5.181\pm 0.003^{\ddagger}$ | $0.71130\pm 0.00005$ | $0.05\pm 0.01$
171988782 | 258048 | 10.02 | F4 EuCr(Sr) | 6370 | 20 | No signature | $1.962238\pm 0.000005$ | $0.55\pm 0.01$
|  |  |  |  |  |  | $1.975095\pm 0.000023$ | $0.13\pm 0.01$
264509538 | K10685175 | 11.79 | A4 Eu | 7970 | 14,15 | $3.1029\pm 0.0005^{\ddagger}$ | $2.216610\pm 0.000006$ | $0.57\pm 0.03$
272598185 | K10483436 | 11.16 | A7 SrEuCr | 7980 | 14,15 | $4.2857\pm 0.0006$ | No signal in TESS data | <0.05
273777265 | K6631188 | 13.38 | F0 Sr | 7500 | 14,15 | $2.519\pm 0.002^{\ddagger}$ | $1.49349\pm 0.00001$ | $1.45\pm 0.16$
286992225 | 2553-480-1 | 11.24 | A9 SrEu | 7490 | 23 | No signature | $2.69128\pm 0.00002$ | $0.32\pm 0.03$
|  |  |  |  |  |  | $2.72616\pm 0.00001$ | $0.54\pm 0.03$
302602874 | 2488-1241-1 | 10.86 | A6 SrEu | 8160 | 21 | $3.0900\pm 0.0003$ | $2.283125\pm 0.000002$ | $2.12\pm 0.02$
Candidate roAp |  |  |  |
9171107 | 2479-429-1 | 9.36 | Unknown | 6770 | 20 | No signature | $1.50971\pm 0.00004$ | $0.053\pm 0.009$
|  |  |  |  |  |  | $1.52902\pm 0.00002$ | $0.108\pm 0.009$
|  |  |  |  |  |  | $1.53502\pm 0.00002$ | $0.094\pm 0.009$
91224991 | 191380 | 8.49 | F8 | 6710 | 14 | No signature | $1.159876\pm 0.000002$ | $0.961\pm 0.008$
275642037 | 4330-716-1 | 9.52 | F0 | 7710 | 18 | $2.8745\pm 0.0003$ | $1.13943\pm 0.00003$ | $0.08\pm 0.01$
|  |  |  |  |  |  | $1.16939\pm 0.00002$ | $0.17\pm 0.01$
298052991 | 4554-625-1 | 8.8 | A2 | 7600 | 14, 21, 21, 26 | $10.5852\pm 0.0001$ | $2.217569\pm 0.000003$ | $0.023\pm 0.004$
|  |  |  |  |  |  | $2.246466\pm 0.000002$ | $0.038\pm 0.004$
|  |  |  |  |  |  | $2.291038\pm 0.000001$ | $0.051\pm 0.004$
405892692 | 3567-1092-1 | 8.99 | F0 | 7230 | 14, 15 | $0.3786\pm 0.0001^{\dagger}$ | $1.17082\pm 0.00002$ | $0.038\pm 0.006$
429251527 | 2185-478-1 | 10.20 |  | 7920 | 15 | No signature | $1.77798\pm 0.00001$ | $0.45\pm 0.02$
445796153 | 34740 | 7.22 | A0p | 8510 | 19, 26 | $5.5721\pm 0.0004$ | $0.601908\pm 0.000002$ | $0.022\pm 0.003$
|  |  |  |  |  |  | $0.675849\pm 0.000002$ | $0.035\pm 0.003$

As with Paper I, we present the numerical results of the reference team to
provide a homogeneous data set both within this paper and across the two
papers. The results have been verified with the WG4 members, and discrepancies
were resolved with secondary checks.

Furthermore, we use the same approach as in Paper I which briefly comprises
of: for each star, we combined available sectors to produce a single light
curve for analysis. We calculated a Discrete Fourier Transform, following
Kurtz (1985), using the PDC_SAP data obtained from the MAST servers. Initially
we searched in the low-frequency range (up to 0.11 mHz; 10 d -1) to identify
signs of rotational variability. Where present, we fitted a harmonic series by
non-linear least squares to determine the stellar rotation frequency, and used
the highest amplitude peak to determine the rotation frequency, in some cases
this was the second harmonic of the rotation frequency. Where no rotational
variability was found, we also checked the SAP light curve for signs of
rotation as the SPOC pipeline can remove low-frequency astrophysical signal.

Subsequently, we removed low-frequency peaks (rotational or instrumental) via
iterative pre-whitening of the light curve to a noise level determined in the
range $2.3-3.3$ mHz ($200-300$ d -1). A new amplitude spectrum was calculated
to the Nyquist frequency, and any signals found were extracted through non-
linear least squares fitting. Both the derived rotation period and the
pulsation frequency(ies) for each star are listed in Table 1. We provide only
the pulsation mode frequencies and not rotationally split sidelobes; any
sidelobes detected are mentioned in the text, and indicated on the appropriate
figure. Where multiplets due to oblique pulsation exist, we apply the
relations of Kurtz et al. (1990) to investigate the geometry of the pulsation
mode as derived by the multiplet amplitudes. For a dipole mode, the multiplet
amplitudes give a relation between the inclination angle, $i$, and the angle
of obliquity, $\beta$, that is the angle between the rotation and pulsation
axes. When conducting these tests we set a zero point in time for the linear
least squares fit such that the phases of the $\pm\nu_{\rm rot}$ sidelobes are
equal. It is expected that all peaks in a multiplet have equal phase for a
non-distorted mode, thus applying the oblique pulsator model provides insight
to the mode structure.

For stars that have previously been discussed at length in the literature,
with use of the TESS data, we do not present an in-depth analysis unless
significant differences in the results were found. We do, however, include
these stars in Table 1 to provide a complete inventory of TESS observations of
roAp stars in Cycle 2. For all stars newly classified as roAp stars in this
work, and roAp stars that have been discovered in TESS data, we provide plots
of their pulsation frequencies. For the known roAp stars, we provide plots in
Appendix C unless there is new information in the TESS data.

Where available, we provide the Strömgren-Crawford indices for a given object.
We used these values, in conjunction with the calibrations of Crawford (1975,
1979) to determine if the values are indicative of a chemically peculiar star.

###  4.1 New TESS roAp stars

We classified the following stars as new roAp stars based on the presence of
high frequency pulsation in the target and either an Ap spectral
classification, the presence of multiplets in the amplitude spectrum split by
the stellar rotation frequency, or Strömgren-Crawford indices that indicate a
chemically peculiar star. While some stars already appear in the literature as
showing rapid oscillations, they were not admitted to the roAp class. Here we
provide a careful consideration of the available evidence to rectify previous
oversights.

####  4.1.1 TIC 101624823

TIC 101624823 (HD 100598) has a spectral classification in the literature of
A2 (Cannon & Pickering, 1919). Masana et al. (2006) estimate the effective
temperature to be 6800 K, based on $V$ and 2MASS IR photometry, and Stassun et
al. (2019) estimate $\log g=3.8$ (cm s-2). The surface gravity was not
obtained via spectroscopy, but calculated from the reported mass and radius.
In addition, the value for the effective temperature of 7000 K and for the
surface gravity $\log g=3.85$ (cm s-2) are extracted from the Gaia
Collaboration (2022) Gaia DR3 catalogue. These values are extracted from GSP-
Phot Aeneas best library using Bp/Rp spectra, apparent G magnitude and
parallax. The final result is the median of the MCMC samples. The literature
values of radial velocity for this star are $-15.45\pm 0.33$ km s-1 measured
by Gaia Collaboration (2018), with a more recent value from the Gaia
Collaboration (2022) Gaia DR3 catalogue of $-15.64\pm 0.19$ km s-1, thus both
in agreement. This star appears in the Strömgren-Crawford measurements of
Paunzen (2015) with values of $b-y=0.223$, $m_{1}=0.157$, $c_{1}=0.672$,
H$\beta=2.714$, which give $\delta m_{1}=0.018$ and $\delta c_{1}=0.105$. Both
of these values indicate a chemically normal star, given the H$\beta$ value.
There are no magnetic field measurements for this star in the literature.

TESS data for TIC 101624823 used in this work were collected during sector 22.
The data show a clear rotational signature of $4.050\pm 0.001$ d (Fig. 1).
This is in agreement with the value reported by Balona (2022) using the same
data, although the previous author did not include an error on the
measurement. After removing the rotation signal from the data, we analysed the
high frequency peak ($1.44176\pm 0.00001$ mHz; $124.5678\pm 0.0009$ d -1),
which was also noted by Balona (2022) but the star was not admitted to the
roAp star class in that work. Here we rectify that oversight with the
identification of a rotationally split sidelobe at $\nu-\nu_{\rm rot}$ (at S/N
$\sim 4.5$) as is expected from oblique pulsations in roAp stars, which is
shown in Fig. 2 by the vertical dotted line. A second sidelobe is identifiable
(at $\nu+\nu_{\rm rot}$), albeit at low S/N ($\sim 3.1$), indicating the
presence of a triplet, and a dipole mode.

Figure 1: Phase folded light curve of TIC 101624823, phased on a period of
$4.050\pm 0.001$ d. The data are binned 50:1. Figure 2: Amplitude spectra of
TIC 101624823. The pulsation mode is identified by the vertical dotted line,
with the dashed lines showing the locations of the rotationally split
sidelobes.

With these two sidelobes, we are able to apply the oblique pulsator model (as
described above) to derive $\tan i\tan\beta=0.369\pm 0.071$. We also found
that the mode is slightly distorted when investigating the phase relations
between the mode and the sidelobes. We found that pulsation maximum occurs at
rotation phase 0.46 in Fig. 1, hence the pulsation pole is located close to
the principal abundance spot that gives rise to the rotational light
variations. Hence this star is typical of the roAp star oblique pulsators in
that the pulsation pole lies close to the magnetic pole.

To further cement its membership of the roAp class, we have obtained a
spectrum from LAMOST. While the data are of low S/N, there is clear presence
of Cr ii in the spectrum (Fig. 43), with the possible presence of Sr ii and Eu
ii, but at a lower confidence. Therefore, we classified this star as an Ap
Cr(SrEu) star. This shows that Ap stars with Strömgren-Crawford indices that
are only slightly deviant from normal stars, can be roAp stars.

####  4.1.2 TIC 165052884

TIC 165052884 (HD 51561) has a spectral classification of A5 (Cannon &
Pickering, 1918b). Stassun et al. (2019) estimate $T_{\rm eff}=6900$ K and
$\log g=4.18$ (cm s-2). The effective temperature is derived from dereddened
Gaia Bp-Rp colour. As with the previous star, this value is calculated using
the mass and radius estimates. The Gaia DR3 (Gaia Collaboration, 2022) gives
$T_{\rm eff}=6850$ K and $\log g=4.22$ (cm s-2).

TESS observed TIC 165052884 in sector 20 of Cycle 2, with the data analysed by
Balona (2022) who measured a rotation period (using sector 20 and 44 data) of
$P_{\rm rot}=17.857$ d and a pulsation frequency of $2.177$ mHz ($\nu$ =
188.069 d -1). However, our analysis cannot reproduce the rotation results of
Balona (2022), even if we include the sector 44 data. We further investigated
this discrepancy by analysing the SAP data, which does indeed show variability
that can be attributed to rotation. However, the signal indicated a rotation
period about the same length of the data ($P_{\rm rot}\sim 22$ d compared to a
data set length of $\sim 26$ d), so cannot be precisely determined.

The high frequency pulsation mode in TIC 165052884 is found at $2.176721\pm
0.000007$ mHz ($188.0687\pm 0.0006$ d -1; Fig. 3), which is in agreement with
Balona (2022). After pre-whitening this signal, there is an indication of a
much lower amplitude mode at $2.17566\pm 0.00004$ mHz ($187.977\pm 0.003$ d
-1) which is separated by the principal peak by a frequency consistent with
half of the presumed rotation frequency ($\sim 1.06$ $\muup$Hz; $0.09$ d -1;
10.9 d). Again, more data are required to confirm this detection.

Figure 3: Amplitude spectrum of TIC 165052884 with the pulsation mode
identified with the vertical dotted line.

We admitted TIC 165052884 to the roAp class based on the pulsation and the
tentative detection of a rotational sidelobe to the pulsation mode.

####  4.1.3 TIC 233200244

TIC 233200244 (HD 161846) was classified as A3 in the Henry Draper Catalogue
(Cannon & Pickering, 1922). From photometry, Pickles & Depagne (2010) give a
similar spectral type of A5 V. The TIC gives $T_{\rm eff}=8200\pm 150$ K, with
similar values of 8050 K and 8100 K obtained by McDonald et al. (2017) and
Tonry et al. (2018), respectively, while the Gaia DR3 lists $T_{\rm eff}$ as
8000 K. The star was analysed by Balona (2022) who classified it as a new
variable A star, with a rotation period of $P_{\rm rot}=7.299$ d (without an
error) and a pulsation frequency of $1.44$ mHz ($124.471$ d -1), which also
showed rotational sidelobes.The star also appears in the catalogue by Skarka
et al. (2022) who classified it as a rotationally modulated star, with a
period of 7.246 d, and a candidate roAp star after studying all A and F stars
in TESS’s northern continuous viewing zone.

TESS observed the star in all sectors of Cycle 2 except sector 20. This allows
us to derive a precise rotation period of $7.25002\pm 0.00006$ d. A folded
light curve is shown in Fig. 4. We proceeded to prewhiten this signal from the
individual sectors before analysing the pulsation modes in this star, with the
resultant amplitude spectrum shown in Fig. 5. We found two pulsation modes at
$1.261462\pm 0.000002$ mHz ($108.9903\pm 0.0001$ d -1) and $1.4390374\pm
0.0000005$ mHz ($124.33283\pm 0.00005$ d -1) separated by $177.576\pm
0.002\,\muup$Hz, which could be three times the large frequency
separation555defined as the frequency difference between two consecutive modes
of the same degree ($\sim 60\,\muup$Hz), when scaling from the solar value.

Figure 4: Phase folded light curve of TIC 233200244, phased on a period of
$7.25002\pm 0.00006$ d. The data are binned 200:1. Figure 5: Amplitude
spectrum of TIC 233200244 showing the two pulsation modes (marked by the
vertical dotted lines) and the rotationally split sidelobes of the higher
frequency mode.

The higher frequency mode is flanked by rotational sidelobes split by exactly
the rotation frequency, indicating the mode is an $\ell=1$ dipole mode. Given
their presence, we applied the oblique pulsator model to test the phase
relations and determine whether the mode is distorted. We found there is a
little distortion to the mode, with the sidelobes having a phase of $-0.553\pm
0.030\,$rad and the pulsation mode having $-0.910\pm 0.031\,$rad. The time
zero point for this calculation corresponds to rotation phase 0.68 in Fig. 4,
i.e., at TESS light maximum.

Given the detection of the pulsations and the sidelobes, coupled with a
clearly stable rotational light curve, we admitted this star to the class of
roAp stars.

####  4.1.4 TIC 259017938

TIC 259017938 (HD 210684) has been classified F0 (Cannon & Pickering, 1924).
Kervella et al. (2019) revealed the existence of a physical companion orbiting
TIC 259017938 from the influence on the star’s proper motion. Assuming
$M_{1}=2.03\pm 0.10$ M⊙ (Girardi et al., 2000) and $R_{1}=2.66\pm 0.13$ R⊙
(Kervella et al., 2004), they found the mass of the companion and the radius
of its orbit to be $M_{2}=80_{-10}^{+23}$ MJup and 1.892 au, respectively.
Strömgren-Crawford indices are given by Paunzen (2015) as: $b-y=0.160$,
$m_{1}=0.196$, $c_{1}=0.824$ and H${\beta}=2.570$. We derive $\delta
m_{1}=0.066$ and $\delta c_{1}=0.619$. These do not indicate an Ap star,
however we note that the $b-y$ and H$\beta$ indices do not agree. Paunzen
(2015) combined two consistent values of $b-y$, while only reporting one value
of H$\beta$. When using $b-y$ as a proxy for H$\beta$ (corresponding to 2.786;
Crawford, 1975) we found $\delta m_{1}=0.002$ and $\delta c_{1}=0.070$ which
do not change our conclusion.

TESS observed TIC 259017938 during sectors 15 and 16 and revealed the star to
be a rotationally and pulsationally variable star (Balona, 2022). We
determined a rotation period of $5.0226\pm 0.0005$ d (Fig. 6), which differs
from the previously published value (of $P=5.201$), although that value has no
associated error. After removing the signature of rotation, we identified a
single pulsation mode in the star at $1.352116\pm 0.000006$ mHz ($116.8228\pm
0.0005$ d -1) that showed a rotationally split multiplet (Fig. 7). We again
applied the oblique pulsator model to this dipole triplet to investigate the
mode distortion and found the phase of the pulsation mode ($-2.48\pm 0.05$
rad) differs from the sidelobes ($-2.17\pm 0.09$ rad) by $3\,\sigma$,
indicating possible slight mode distortion. The pulsation maximum corresponds
to rotation phase 0.21 in Fig. 6, i.e., just before TESS light maximum.

Figure 6: Phase folded light curve of TIC 259017938, phased on a period of
$5.0226\pm 0.0005$ d. The data are binned 100:1. Figure 7: Amplitude spectrum
of TIC 259017938 showing the pulsation mode (marked by the vertical dotted
line) and the rotationally split sidelobes.

We have also obtained three medium resolution spectra from the LAMOST database
to search for chemical peculiarities (Fig. 41). We identified lines of Pr iii,
Nd ii & iii and La ii amongst others, which indicate the star to be an Ap
star, thus providing further evidence to admit the star to the roAp class.

####  4.1.5 TIC 335457083

TIC 335457083 (HD 48409), was classified as A3 in the Henry Draper Catalogue
(Cannon & Pickering, 1918b). The TIC gives $T_{\rm eff}=7500\pm 140$ K and
Gaia DR3 7500 K with a small uncertainty. The literature values, however,
range from 9100 K (Stassun et al., 2018) down to 6900 K (Schofield et al.,
2019), with intermediate values of 8700 K, 8750 K and 7650 K (Wright et al.,
2003; Ammons et al., 2006; McDonald et al., 2017), respectively. Based on its
Strömgren-Crawford indices, of $b-y=0.213$, $m_{1}=0.308$, $c_{1}=0.517$ and
H$\beta=2.838$ (Hauck & Mermilliod, 1998), which give $\delta m_{1}=-0.100$
and $\delta c_{1}=-0.332$, and a large $\Delta p$ “peculiarity” parameter of
6.779 (defined by Masana et al. (1998)), the star was selected to be observed
by the Nainital-Cape Survey (Joshi et al., 2006), but no variability was found
in this targeted ground-based photometric study. Previously, Balona (2022)
reported a rotation period of $2.907$ d and a pulsation frequency of $2.084$
mHz (180.075 d -1) in this star using the TESS data.

TESS observed TIC 335457083 in sector 20 from which we derived a rotation
period of $2.9139\pm 0.0001$ d (Fig. 8). At high frequencies, we inferred the
presence of four pulsation modes (Fig. 9). In increasing frequency order, we
found a doublet and inferred the presence a mode from the observation of two
peaks separated by twice the rotation frequency (i.e., a mode at $2.08819\pm
0.00002$ mHz; $180.419\pm 0.002$ d -1), a triplet (centred on a mode at
$2.20575\pm 0.00003$ mHz; $190.577\pm 0.002$ d -1), followed by two single
peaks at $2.24835\pm 0.00003$ mHz ($194.258\pm 0.003$ d -1) and $2.29691\pm
0.00005$ mHz ($198.453\pm 0.004$ d -1). The doublet and triplet show very
different ratios of the pulsation mode amplitude and the amplitude of the
rotationally split sidelobes. For both modes to be dipole modes, we would
require two pulsation axes in this star. Therefore, we assumed the doublet to
be a quadrupole mode, and the triplet to be a dipole mode. Under this
assumption, we calculated the values of $i$ and $\beta$ following Kurtz et al.
(1990) such that $i=56^{\circ}$ and $\beta=45^{\circ}$. This leads to
$i+\beta=100^{\circ}$ which is consistent with the partial double wave of the
rotation curve, supporting our choice of mode identifications. Of the
observed, or inferred modes, there is no regular spacing that can be
interpreted as the large frequency separation. However, there are further
peaks above the noise in the amplitude spectrum of this star too, but further
data are required to reduce the noise level to allow confident extraction of
those possible mode frequencies. These additional modes may lead to the
identification of the large separation frequency in this star.

Figure 8: Phase folded SAP light curve of TIC 335457083, phased on a period of
$2.9139\pm 0.0001$ d. The data are binned 50:1. Figure 9: Amplitude spectrum
of TIC 335457083 showing the pulsation modes (marked by the vertical dotted
lines) and the rotationally split sidelobes (marked with the vertical dashed
lines).

Given both the strong indication that this star is chemically peculiar from
the Strömgren-Crawford photometry, and the presence of modes with rotational
splitting, we admitted this star to the class of roAp stars.

####  4.1.6 TIC 445493624

TIC 445493624 (HD 11948) has several spectral classifications in the
literature: F0p (Hoag & Applequist, 1965), A5 Am/p (Olsen, 1980), A5 SrEu
(Renson, 1988), A5 SrCrEu (Gomez et al., 1998), all of which indicate this to
be a chemically peculiar star. In addition, Strömgren-Crawford indices have
also been measured several times (e.g., Perry & Johnston, 1982) with values
being consistent with: $b-y=0.115$, $m_{1}=0.243$, $c_{1}=0.880$ and
H$\beta=2.873$ (Paunzen, 2015), which are also consistent with a chemically
peculiar A star (with $\delta m_{1}=-0.041$ and $\delta c_{1}=-0.036$). The
effective temperature of the star is reported consistently across the
literature, e.g., $T_{\rm eff}=8050$ K (McDonald et al., 2012), $T_{\rm
eff}=8250$ K (Joshi et al., 2016) and the TIC providing $8050$ K. Kervella et
al. (2019) report a mass and radius of $M=2.20$ M⊙ and $R=2.15$ R⊙. The Gaia
DR3 parallax provides a distance of $180\pm 1$ pc, which is at odds to the
report that TIC 445493624 is a member of the NGC 744 open cluster (Niedzielski
& Muciek, 1988).

The star has a constant radial velocity in the literature of 32 km s-1 (de
Bruijne & Eilers 2012, Kervella et al. 2019, Brandt 2021), and has a root-
mean-squared longitudinal magnetic field of $\langle B_{\ell}\rangle=500\pm
50$ G with extreme values of the longitudinal component being $B_{\ell}$
$-550$ and $+300$ G (Romanyuk & Kudryavtsev, 2008).

The star was searched for pulsations during the Nainital-Cape survey (Joshi et
al., 2006), but none was found. Since then the TESS data have been used by
Balona (2022) to identify a rotation period of $7.333$ d, and a pulsation
frequency of $1.225$ mHz (105.857 d -1). In that study, the star was
classified as a possible roAp star.

TESS observed TIC 445493624 during sector 18. To derive the rotation period,
we cleaned the SAP data of outlying points (which constituted about 5 per cent
of the data) since the signal in the PDC_SAP data had been altered by the
pipeline corrections. We derived a rotation period of $P_{\rm rot}=7.288\pm
0.002$ d, as shown in Fig. 10. To inspect the high frequency variability, we
returned to the PDC_SAP data and removed the low-frequency peaks to the noise
level in the frequency range of interest. Here we found significant evidence
of variability (Fig. 11). There are many peaks with amplitudes significantly
above the noise level, however many are unresolved. We extracted a single
mode, which itself does not resemble the window function, at a frequency of
$1.22522\pm 0.00003$ mHz ($105.859\pm 0.002$ d -1). Since the frequency
resolution for the data set is 0.4 $\mu$Hz, which is significantly smaller
than the expected small separation in roAp stars, the evidence suggests
amplitude and/or frequency variability of the mode. This is not unprecedented
in the Ap stars, even on short time scales, (e.g., HD 60435; Balona et al.
2019).

Figure 10: Phase folded SAP light curve of TIC 445493624, phased on a period
of $7.288\pm 0.002$ d. The data are binned 50:1. Figure 11: Amplitude spectrum
of TIC 445493624. We have extracted the pulsation mode marked with the
vertical dotted line. The other variability clustered around 1.235 mHz is
unresolved in this short set of data.

To confirm the chemical peculiarity in this star, we have obtained a spectrum
using the HERMES spectrograph (Figs. 38 & 39). We found clear presence of Sr
ii and Eu ii, as well as enhancements of other rare earth elements in the
region around 6150 Å. Using the procedures outlined above, we derived the
following parameters from the spectrum: $T_{\rm eff}=8370\pm 90$ K, $\log
g=4.0\pm 0.3$ (cm s-2) and $v\sin i=14\pm 2$ km s-1.

With the evidence we have gathered, and that in the literature, we admitted
TIC 445493624 to the class of roAp stars.

####  4.1.7 TIC 467074220

TIC 467074220 (HD 40142) has several classifications in the literature: Ap Sr-
Eu (Cowley & Cowley, 1965); F0p (Nelson & Kreidl, 1993); F0 (Cannon &
Pickering, 1918b). Its estimated effective temperature is $T_{\rm eff}=7200$ K
from Gaia DR2 (Gaia Collaboration et al., 2018; Gaia Collaboration, 2018) and
6950 K from (McDonald et al., 2012), while Shang et al. (2022) determined 7580
K from LAMOST spectra. Gaia DR2 also provided $\log L/{\rm L_{\odot}}=1.37$.
Hauck & Mermilliod (1998) provide Strömgren-Crawford indices of: $b-y=0.216$,
$m_{1}=0.175$, $c_{1}=0.869$ and H$\beta=2.814$, giving $\delta m_{1}=0.031$
and $\delta c_{1}=0.064$, indicating a normal star.

This star has a magnetic field first reported by Romanyuk & Kudryavtsev (2008)
with a root mean value of $\langle B_{\ell}\rangle=700\pm 50$ G with three
magnetic field observations from the 6-m telescope of the Special
Astrophysical Observatory of the Russian Academy of Sciences. The extremes
measured were $-780$ G and $+780$ G.

Pulsations have been searched for in this star before by Nelson & Kreidl
(1993) using ground-based $V$ and $B$ photometric data, but with none found.
No other searches have been published.

TESS observed this star during sector 19. The data show a clear rotation
signature with a period of $P_{\rm rot}=5.4195\pm 0.0004$ d (Fig. 12). This is
the first report of this signature in the literature. Further, we detected two
pulsation modes (Fig. 13) at $0.70462\pm 0.00006$ mHz ($60.879\pm 0.005$ d -1)
and $0.72476\pm 0.00003$ mHz ($62.619\pm 0.002$ d -1). These modes are similar
in frequency to $\delta$ Sct modes, but there are only two modes detected
which is unusual for $\delta$ Sct stars. At this slightly higher frequency,
there are more examples of roAp stars with similar pulsations in the
literature (e.g., HD 177765; Alentiev et al. (2012); Holdsworth (2016)).

Figure 12: Phase folded light curve of TIC 467074220, phased on a period of
$5.4195\pm 0.0004$ d. The data are binned 50:1. Figure 13: Amplitude spectrum
of TIC 467074220. The two pulsation modes marked with vertical dotted lines.

We have extracted a spectrum of TIC 467074220 from the LAMOST archive to
confirm the spectral classification (Fig. 46). There is obvious over
enhancements of Sr ii and Cr ii, with an indication of Eu ii.

With a combination of the rotational modulation in the star, the detected
magnetic field and observed chemical peculiarities, we admitted this star to
the class of roAp.

###  4.2 roAp stars previously discovered by TESS

In this section, we present the roAp stars detected in TESS data by our method
but which have already been published as roAp stars in the literature.

####  4.2.1 TIC 21024812

TIC 21024812 (HD 14522) was originally identified as a chemically peculiar
magnetic star by Schneider (1986), and Renson & Manfroid (2009) classified it
as A2 SrEu. Muñoz Bermejo et al. (2013) estimated the star’s effective
temperature using principal component analysis techniques to compare it to a
homogeneous library of stellar spectra, and derived $T_{\rm eff}=7750\,K$, in
general agreement with the TIC value of $8050\pm 130$ K (Stassun et al., 2019)
and the Gaia DR3 value of 7950 K (Gaia Collaboration, 2020). Gaia DR3 also
derived a distance of 282 pc, $\log g=3.93$ (cm s-2) and [Fe/H] = -0.11, while
the TIC estimated the stellar radius to be $2.49\pm 0.08$ R☉ and mass to be
$1.96\pm 0.30$ M☉.

Bernhard et al. (2020) made use of archival photometric data from a variety of
ground-based surveys to estimate the rotational period to be $26.36\pm 0.01$
d, with an amplitude in $V$ of about 0.01 mag, while Joshi et al. (2006)
conducted a 1.4-hr search for pulsations using a three-channel photometer on
the ARIES 1.04-m Sampurnanand telescope, but found no variability.

TIC 21024812 was reported as an roAp star by Balona (2022) who derived a
rotation period of $P_{\rm rot}=13.158$ d and a pulsation frequency of $1.103$
mHz ($95.265$ d -1) using TESS sector 18 data. However, our more detailed
analysis of the same sector 18 observations suggests that the rotation period
is about twice that reported. We used the SAP light curve, which showed
significant variability consistent with stellar rotation, to find that the
signal is non-repeating over the light curve duration of $24.356$ d. This is
consistent with the rotation period derived by Bernhard et al. (2020) of
$26.36\pm 0.01$ d. Further observations of this star are required to constrain
the rotation period with precision.

The short period variability seen in the amplitude spectrum of this star (Fig.
14) is seen at a frequency of $1.10259\pm 0.00002$ mHz ($95.263\pm 0.002$ d
-1) with the indication of a sidelobe on the higher frequency side of the
pulsation. The peak in the amplitude spectrum appears broad which may be
caused by amplitude/phase modulation, or the presence of unresolved sidelobes.

Figure 14: Amplitude spectrum of TIC 21024812, with the pulsation mode
indicated with the vertical dotted line, and the suspected positive rotational
sidelobe with the dashed line. The peak is seen to be broad, indicating
amplitude/phase modulation, or unresolved sidelobes.

Further to the classification of TIC 21024812 being a chemically peculiar star
in the literature, we have two sources of spectra of this star: LAMOST and
HERMES. The LAMOST spectrum was obtained in its low resolution mode, and can
be seen in Fig. 40, while the HERMES spectrum is shown in Figs. 38 & 39. From
the LAMOST spectrum, we classified this star as A8 SrEu(Cr). Using the
procedures outlined above, we derived the following parameters from the HERMES
spectrum: $T_{\rm eff}=8250\pm 70$ K, $\log g=4.0\pm 0.3$ (cm s-2) and $v\sin
i=8\pm 3$ km s-1.

####  4.2.2 TIC 25676603

TIC 25676603 (TYC 2194-2347-1) is a slowly rotating Fp star, with particularly
strong absorption in the Sr ii 4077 Å line and $v\sin i<1.1$ km s-1 (North &
Duquennoy, 1991). There are not many mentions of this star in the literature
where detailed studies have been conducted. The Gaia DR3 gives an effective
temperature of $T_{\rm eff}=6650$ K and a $\log g=4.1$ (cm s-2). These are
consistent with the spectral types of Ap SrEu (Bidelman, 1966) and the Fp
class.

TIC 25676603 was first reported as an roAp star by Balona (2022) who claimed
to identify the rotation period to be $P_{\rm rot}=5.495$ d and a pulsation
mode at a frequency of $1.820$ mHz ($157.205$ d -1). However, our analysis of
the TESS sector 15 data do not show a clear signal of rotation. We analysed
the SAP data to investigate if a long rotation period has been removed by the
PDC pipeline. Indeed, we found some variability that is consistent with a long
rotation period, as would be expected from the previous measurement of the
upper limit on $v\sin i$. We therefore concluded that the rotation period is
longer than the current TESS data set, and the value published by Balona
(2022) should be disregarded as noise or of instrumental origin.

We identified three pulsation modes in the PDC_SAP sector 15 data for this
star, at frequencies of $1.787321\pm 0.000027$ mHz ($154.4245\pm 0.0024$ d
-1), $1.819500\pm 0.000002$ mHz ($157.2048\pm 0.0002$ d -1) and $1.846724\pm
0.000008$ mHz ($159.5569\pm 0.0007$ d -1). All three peaks show structure
(Fig. 15), suggesting that the rotation period is not fully resolved in 27 d
of TESS data, confirming our previous conclusion. The three modes are not
separated by the same frequency spacing ($32.18\pm 0.03\,\muup$Hz and
$27.22\pm 0.01\,\muup$Hz), but since the modes are not fully resolved this
view may change with the addition of future observations.

Figure 15: Amplitude spectrum of TIC 25676603, with the pulsation modes
indicated with the vertical dotted lines.

####  4.2.3 TIC 26833276

TIC 26833276 (HD 10682) is not well studied in the literature. The only
classification giving an indication that this is a chemically peculiar star is
from Clausen & Jensen (1979) with F0 Vp Sr. However, this is at odds with the
classification of A3 (Cannon & Pickering, 1918a). Catalogue values of the
effective temperature range from 6750 K (McDonald et al., 2012) to 8700 K
(Wright et al., 2003), while Gaia DR3 gives 7300 K (Gaia Collaboration, 2022).
The hottest temperature is based on the spectral type alone, while the others
are derived from measurements. Therefore we suggest the effective temperature
is closer to 7000 K which supports the classification of an F0 star.

Balona (2022) classified the star as an roAp star given the presence of a
pulsation mode at a frequency of $1.583$ mHz ($136.786$ d -1), as well as a
rotation period of $10.417$ d, as seen in the TESS sector 17 data. However, a
detailed view of the same TESS data here does not support the conclusion of
the rotation period. This is another case where the PDC pipeline has altered
the rotation signal since it appears to be longer than the data set. When
inspecting the SAP data, it is clear there is a partial rotation curve that
does not repeat. We therefore conclude that the rotation period is greater
than the sector length, i.e., >25 d, and the previous value presented in the
literature should be ignored.

The pulsations in this star are irrefutable. There are two groups of two
modes; the lower frequency pair appear at $1.58317\pm 0.00002$ mHz
($136.786\pm 0.001$ d -1) and $1.60714\pm 0.00003$ mHz ($138.857\pm 0.002$ d
-1) and are present in all of the sector 17 observations. The two modes at
higher frequency are transient in nature and only appear in the second orbit
of sector 17 (Fig. 16). These modes are at $2.74058\pm 0.00004$ mHz
($236.786\pm 0.003$ d -1) and $2.80741\pm 0.00004$ mHz ($242.560\pm 0.003$ d
-1). We are unsure of the nature of the high-frequency pair.

Figure 16: Amplitude spectra of TIC 26833276 calculated from the two TESS
orbits when it was observed. The amplitude spectrum with positive amplitude is
from orbit 41, with two pulsation modes around 1.6 mHz. The amplitude spectrum
with negative amplitude is from orbit 42, showing the emergence of two further
modes at high frequency (around 2.8 mHz).

This star has LAMOST MRS data (Fig. 42) available in the archive which we
analysed to identify chemical peculiarities and to resolve the discrepancy
between the spectral types. We found an overabundance of Nd iii and La ii,
amongst others, confirming the star to be chemically peculiar. By fitting the
Hα line, we determine an effective temperature of $7200\pm 200$ K. Therefore,
we can confirm the star is an F0p chemically peculiar star.

####  4.2.4 TIC 72392575

TIC 72392575 (HD 225578) has an uncertain spectral classification; it is given
as ApSr: by Cowley & Cowley (1964), while it is classified as an A5 star in
the Henry Draper Catalog and Extension (Cannon & Pickering, 1923). More
recently, Renson & Manfroid (2009) gave the spectral classification for this
star as A5 Sr.

Sikora et al. (2019a) and Stassun et al. (2019) estimate the effective
temperature and $\log g$ values to be 7550 K and 4.14 (cm s-2), respectively.
The effective temperature is determined from the dereddened Bp-Rp colour,
while the $\log g$ value is derived from the given mass and radius. Other
estimations of $T_{\rm eff}$ are 7650 K (Ammons et al., 2006) and 7850 K
(Anders et al., 2019)

Balona (2022) listed this star as a new roAp star discovered using TESS data,
and also classified it as an $\alpha^{2}$ CVn variable with a rotation period
of $P_{\rm rot}=3.922$ d. He also gave an estimate of the luminosity $\log
L/\rm{L}_{\odot}$= 1.07 using Gaia EDR3 parallaxes (Gaia Collaboration et al.,
2016, 2021) in conjunction with interstellar reddening corrections from
Gontcharov (2017) and a bolometric correction calibration by Pecaut & Mamajek
(2013).

A previous search for pulsational variability did not yield a positive
detection down to 1.6 mmag in the amplitude spectrum (Paunzen et al., 2012).
However, Balona (2022) found roAp variability in the TESS light curve, with
the highest amplitude frequency at $1.573$ mHz ($135.944$ d -1). There are no
magnetic field measurements for this star in the literature.

Our analysis of the TESS light curve, from sector 14, confirms the rotation
period as $3.9016\pm 0.0008$ d (Fig. 17), and the single high frequency
pulsation at $1.57343\pm 0.00003$ mHz ($135.944\pm 0.003$ d -1; Fig. 18).
Despite the short rotational period of this star, we do not detect rotational
sidelobes to the pulsation, suggesting a low value of $i$ or $\beta$ for this
star. However, there is a slight power excess at slightly higher frequency
which may be a signature of a rotational sidelobe, but this is unclear.

Figure 17: Phase folded light curve of TIC 72392575, phased on a period of
$3.9016\pm 0.0008$ d. The data are binned 50:1. Figure 18: Amplitude spectrum
of TIC 72392575, showing the pulsation mode. At slightly higher frequency
there is a power excess which might be a rotational sidelobe (the single sharp
peak).

####  4.2.5 TIC 118247716

TIC 118247716 (HD 12519) has several spectral classifications in the
literature: A5 (Cannon & Pickering, 1918a), A4pSrEuCr (with a comment of
‘composite?’; Clausen & Jensen, 1979) and A2pSrSi (Grenier et al., 1999).
Stassun et al. (2019) estimate $T_{\rm eff}=7050$ K, and $\log g=4.04$ (cm
s-2). The effective temperature value is derived from a dereddened Bp-Rp
colour. The surface gravity is calculated from the reported mass and radius of
the star. Gaia DR3 estimates an effective temperature of 7100 K and $\log
g=4.11$ (cm s-2) (Gaia Collaboration, 2022). There are two consistent radial
velocity estimates for this star: $-5.9\pm 3.3$ km s-1 (Gontcharov, 2006) and
more recently $-8.9\pm 0.6$ km s-1 from the Gaia DR3 data Gaia Collaboration
(2022)

This star was targeted as part of the Nainital-Cape survey (Joshi et al.,
2006) which searched for photometric variability. The star was included in the
target list given its Strömgren-Crawford indices of $b-y=0.238$,
$m_{1}=0.289$, $c_{1}=0.546$ and H$\beta=2.803$ (Paunzen, 2015), giving
$\delta m_{1}=-0.086$ and $\delta c_{1}=-0.239$, being indicative of a
chemically peculiar star, and its $\Delta p$ peculiarity parameter of 5.989
(Masana et al., 1998).

TIC 118247716 was first classified as an roAp star using TESS data (Balona,
2022). We corroborate this with the detection of three pulsation modes in the
typical roAp frequency range (Fig. 19): $1.94247\pm 0.00004$ mHz ($167.829\pm
0.003$ d -1), $1.97093\pm 0.00002$ mHz ($170.2884\pm 0.001$ d -1), and
$2.03280\pm 0.00002$ mHz ($175.634\pm 0.002$ d -1). There appear to be further
modes in this star, but close to the noise level. Thus, we did not extract
them, but suggest this star is revisited when more data are available. We see
no rotationally split sidelobes to the pulsations which is consistent with the
lack of rotational modulation in the light curve.

Figure 19: Amplitude spectrum of TIC 118247716, with three modes clearly
identifiable. Further modes may be present close to the noise level.

This star has a LAMOST low resolution spectrum available in the archive, which
we used to confirm its spectral type of A7p SrEuCr (Fig. 44). This cooler
classification is justified by the lack of convincing Si lines in the
spectrum, which are associated with hotter CP stars, and that the Balmer lines
are well matched with that of an A7 normal star. This cooler classification
also agrees better with the literature effective temperatures.

####  4.2.6 TIC 120532285

TIC 120532285 (HD 213258) is a high proper motion star (Gaia Collaboration,
2020), with a measured radial velocity of $-86.8$ km s-1 (North & Duquennoy,
1991). It is classified as an A3 star by Cannon & Pickering (1924), and an F
str $\lambda$ 4077 star666These stars are spectroscopically similar to Am
stars, but with an abnormally strong Sr ii 4077 Å line (Bidelman, 1981; North,
1987) by Bidelman (1985). Gaia DR2 estimates an effective temperature in the
range 6750 K to 7350 K, a radius range of $1.75-2.09$ R⊙, and luminosity range
of 8.07-8.12 L⊙ (Gaia Collaboration et al., 2018). Paunzen (2015) provides
Strömgren-Crawford indices of $b-y=0.222$, $m_{1}=0.187$ and $c_{1}=0.659$.
Most recently, Mathys et al. (2023) measured a mean magnetic field modulus of
this star to be $\langle B\rangle\sim 3.8$ kG and a longitudinal field of
about $-0.9$ kG, whilst also concluding that the star must have a rotation
period of the order 50 yr. They also suggested that the star could be host to
a substellar companion with an orbital period suspected to be shorter than 100
d. They were also the first authors to report this star as an roAp star, with
three pulsation modes, after analysing TESS data.

TESS observed TIC 120532285 during sector 16. The light curve showed no
signature of rotation, as expected given the conclusions of Mathys et al.
(2023), but does show high frequency variability as previously reported. We
detect three modes in the amplitude spectrum (Fig. 20) at frequencies of
$2.171017\pm 0.000011$ mHz ($187.5759\pm 0.0009$ d -1), $2.198746\pm 0.000008$
mHz ($189.9716\pm 0.0007$ d -1), and $2.226270\pm 0.000006$ mHz ($192.3497\pm
0.0006$ d -1). The separation between the modes (in increasing frequency) is
$27.73\pm 0.01\,\mu$Hz and $27.52\pm 0.01\,\mu$Hz which are plausibly half of
the large frequency separation, given the stellar parameters in the
literature. We note a fourth, but not significant, peak in the amplitude
spectrum that also follows the separation pattern, at the lower frequency side
of the extracted three peaks.

Figure 20: Amplitude spectrum of TIC 120532285. The pulsation modes are
highlighted by vertical dotted lines, while the peak at about 2.145 mHz is not
significant but it does follow separation pattern of the other modes.

####  4.2.7 TIC 129820552

TIC 129820552 (TYC 2322-1440-1) is classified in the literature as an Ap SrEu
star (Bidelman, 1998). The Gaia collaboration, via DR2, provide the following
parameters: $T_{\rm eff}$ in the range $7200-7400$ K; a radius in the range of
$1.63-1.72$ R⊙, and a luminosity range of $7.06-7.41$ L⊙ (Gaia Collaboration
et al., 2018). Previously, Netopil et al. (2017) determined the rotation
period of the star to be 6.221 d. This star also appeared in the work of
Balona (2022) who provided a rotation period of 6.211 d and identified a high
frequency pulsation signal at a frequency of $2.013$ mHz ($173.928$ d -1)
based on the TESS observations.

Using those same data, obtained in sector 18, we derived a rotation period of
$6.230\pm 0.002$ d which differs from the previous determinations (although no
errors are given on previous work). We were also able to identify the
pulsation mode in this star at a frequency of $2.01305\pm 0.00002$ mHz
($173.928\pm 0.001$ d -1; Fig. 21) and note that there are four rotational
sidelobes present in the amplitude spectrum. By selecting the appropriate
zero-point in time, we were able to fit the quintuplet such that the phases of
the peaks were all in agreement, indicating this is a non-distorted quadrupole
mode, and found $\tan i\tan\beta=2.95\pm 0.61$, which implies $i\approx
78^{\circ}$ and $\beta\approx 32^{\circ}$, or vice versa.

Figure 21: Amplitude spectrum of TIC 129820552 with the pulsation mode
identified with the vertical dotted line, with the dashed lines indicating the
rotationally split sidelobes.

####  4.2.8 TIC 394860395

TIC 394860395 (TYC 2666-85-1) has been classified as Ap SrEu type peculiar
star (Bidelman, 1985). Several studies have been carried out to reveal its
magnetic structure. Kudryavtsev et al. (2006) calculated the longitudinal
component of the magnetic field from spectral observations of the depression
at 5200 Å. Their measurements indicated that the star has displayed a magnetic
field with the observed $B_{\ell}$ values ranging from $-520$ to $+540$ G.
Bychkov et al. (2009) calculated the averaged quadratic longitudinal magnetic
field as $\langle B_{\ell}\rangle=380\pm 111$ G based on the measurements by
Kudryavtsev et al. (2006) using the metallic spectral lines. Recently,
Romanyuk et al. (2020) measured the longitudinal magnetic field and radial
velocity values by using the data taken in 2012. Accordingly, they found
$B_{\ell}=-340\pm 40$ G and $V_{\rm{R}}=-32.5\pm 3.5$ km s-1 at JD 2456140.484
and $B_{\ell}=100\pm 50$ G and $V_{\rm{R}}=-31.4\pm 3.0$ km s-1 at JD
2456233.261.

Paunzen et al. (2013) reported that the star has shown a prominent peak at
about 5 mHz in the periodogram of Johnson $B$ photometric data and noted that
such a high frequency had never been detected in any roAp star. However,
Paunzen et al. (2015) could not find any variability at the previously
reported frequency. They gave the effective temperature and interstellar
reddening to be $T_{\rm{eff}}=6800\pm 400$ K and E(B-V) of 0.08 mag,
respectively. Muñoz Bermejo et al. (2013) performed a principal component
analysis to characterise the effective temperature from low-resolution
spectroscopic data and calculated a temperature value of 7300 K.

This star was reported to be a rotationally variable roAp star by Balona
(2022). He measured a rotation period of $P_{\rm rot}=6.667$ d and a pulsation
frequency of $1.180$ mHz ($101.949$ d -1), using TESS data. Here we use the
TESS sector 14 data to refute the previously determined rotation period. There
is no clear indication in the PDC_SAP data that the period above is of an
astrophysical nature. We inspected the SAP data and found significant
variability, although that does not wholly appear astrophysical either. We
show both light curves in Fig. 22.

Figure 22: Comparison of the PDC_SAP light curve (grey) and the SAP light
curve (black) for TIC 394860395. Both light curves show variability, but we
argue neither is indicative of a rotation period. The dimming in the SAP data
are flagged as bad points in the PDC_SAP data, and are excluded from the final
light curve.

The pulsation signature in this star is also somewhat complicated (Fig. 23).
At first inspection, it appeared there were two modes, but after removing
those there remained a third peak exactly between the two previous ones.
Therefore, we have taken the pulsation frequency to be the central peak at
$1.18050\pm 0.00005$ mHz ($101.995\pm 0.004$ d -1) and deduced that the two
outer peaks are in fact sidelobes due to rotation. Those sidelobes indicate
that the rotation period is on the order of $23\pm 2$ d. This is an example of
where caution should be exercised when deducing rotation periods with weak
signals in the low frequency range in Ap stars.

Figure 23: Amplitude spectrum of TIC 394860395 showing the pulsation modes
(marked by the vertical dotted lines) and the rotationally split sidelobes
(marked with the vertical dashed lines).

####  4.2.9 TIC 435263600

TIC 435263600 (HD 218439) was first classified as an A2p: star with Sr, Cr,
and Si peculiar features (Slettebak & Nassau, 1959), and more recently
classified as an A5 IVpSrSi star (Abt, 1985). The star is a known visual
binary (e.g., McAlister et al., 1987, 1990; Balega et al., 1994; Germain et
al., 1999; Scardia et al., 2006), with a close companion ranging in distance
from the primary between 0.47 arcsec to 0.62 arcsec (depending on the epoch),
with a magnitude difference of 0.5 mag (Holden, 1976). The mass of the primary
is $1.6$ M⊙ (Kervella et al., 2019), with the orbital elements of: $P_{\rm
orb}=415\pm 21$ yrs, $e=0.51\pm 0.05$, and the inclination of
$i=165^{\circ}\pm 3^{\circ}$ (Ling, 2010).

Strömgren-Crawford indices were measured by Hauck & Mermilliod (1998) to be:
$b-y=0.187$, $m_{1}=0.138$, $c_{1}=1.008$ and H$\beta=2.841$, giving $\delta
m_{1}=0.070$ and $\delta c_{1}=0.154$. These indices suggest the star is
perhaps metal deficient, but we note that a binary companion will affect the
values and they should not be used to draw conclusions. These indices also
suggest a temperature of about 8200 K using relations of Moon & Dworetsky
(1985), while an effective temperature of 8300 K was measured through the
intensity of the Ca ii K line (Floquet, 1981).

Variability in this star was first reported by Balona (2022) who analysed the
available TESS data. He classified it as an $\alpha^{2}\,$CVn star with both
$\gamma$ Dor and roAp pulsations. We corroborate his conclusion here, although
note the complexities in the amplitude spectrum of the combined sector 17 and
24 TESS data. The top panel of Fig. 24 shows the low frequency variability in
this star. We assumed the highest amplitude peak, which also has a harmonic,
corresponds to the rotation period of the star ($P_{\rm rot}=3.0739\pm 0.0002$
d). We then assumed the remaining peaks, above 0.01 mHz are g-mode pulsations.
However, given the star is a known binary it is unclear as to the source of
the variability, or indeed if one or more of the peaks in the amplitude
spectrum correspond to an orbital period. After removal of the dominant peaks,
significant power remained in this low-frequency range. A longer timebase of
observations is required to resolve these peaks.

Figure 24: Amplitude spectra of TIC 435263600 showing (top) the low frequency
range that indicated either rotational variation, g-mode pulsations, an
orbital companion or a combination these phenomena. The middle panel shows the
pulsation modes (marked by the vertical dotted lines). All modes show signs of
frequency variability making precise determination of the frequencies
difficult. The bottom panel shows the amplitude spectra for the same frequency
range, but plotting the amplitude spectra for sector 17 (positive) and 24
(negative) data separately.

At high frequency (Fig. 24 middle and lower panels) we identified clear signs
of pulsations commensurate with those seen in roAp stars. In this frequency
range there is significant frequency and amplitude modulation of the
pulsations. We show in the bottom panel of Fig. 24 the amplitude spectra of
the two sectors of data, which demonstrate this. It is possible to see the
variability on shorter timescales too, on the order of 13-d TESS orbits or
shorter. Such a phenomenon is becoming commonplace in the roAp stars given the
long timebase, high precision data sets that are now available (e.g.,
Holdsworth, 2021).

Finally, for this star we have retrieved a spectrum from the HERMES archive.
There were two epochs of data, separated by 5 d, which showed very different
signatures. Fig. 45 shows the spectra in the blue spectral region and Hα. The
change in the line profiles suggests there is a close companion with an
orbital period much shorter than the period of 415 yr provided by Ling (2010),
perhaps making this a triple system. Thus we recommend this star be
spectroscopically monitored to study the system in detail. Using the
procedures outlined above, we derived the following parameters from the
spectrum where primarily only one star is seen : $T_{\rm eff}=7950\pm 100$ K,
$\log g=4.0\pm 0.5$ (cm s-2) and $v\sin i=65\pm 9$ km s-1. We note that these
values should be treated cautiously given the binary nature of the star.

###  4.3 Known roAp stars prior to TESS launch

In this section, we present an analysis of the roAp stars which were known
prior to the launch of the TESS mission. As with the new roAp star
discoveries, we present only new information on stars which have already been
discussed in the literature. There are 23 stars which are known to be roAp
stars in the northern ecliptic hemisphere. Of these, 16 were observed by TESS
in 2-min cadence in Cycle 2. Of the 7 that were not observed, 6 did not fall
on a chip, while one star $\beta$ CrB (TIC 383521659; HD 137909) was only
observed at 30-min cadence in FFIs of sector 24.

####  4.3.1 TIC 26418690

TIC 26418690 (KIC 11296437) was discovered to be an roAp star by Hey et al.
(2019) after searching for high frequency pulsations in Kepler long cadence
data using super-Nyquist asteroseismology (Murphy et al., 2013). The star was
later studied by Murphy et al. (2020) who showed it to be the first $\delta$
Sct-roAp hybrid star. We refer the reader to the latter study for a detailed
analysis. The rotation period reported here, $P=7.11\pm 0.02$ d from the
analysis of data from sectors 14 and 15, is in agreement with the more precise
value determined from Kepler observations, and the pulsation mode is recovered
at the expected frequency (Table 1). However, the rotational sidelobes are of
too low amplitude to be recovered in the TESS data. Fig. 47 shows the
amplitude spectrum of this star, in the two regions of known pulsational
variability. The spectral type of this star, A9 EuCr (Table 1), is from Hey et
al. (2019).

The non-detection of the low amplitude signals in the TESS data is not
surprising. Using a pulsating eclipsing binary system, Antoci et al. (2019)
estimated that the redder passband of TESS accounts for an approximate 25 per
cent reduction in the relative amplitude when compared to data from the Kepler
mission. While temperature dependent, this, coupled with the higher noise
level in TESS data compared to Kepler data, explains the non-detection of
previously observed peaks.

####  4.3.2 TIC 26749633

TIC 26749633 (KIC 11031749) is another roAp star discovered by Hey et al.
(2019) in long cadence Kepler data. This star showed no rotation signal in the
two TESS sectors in which it was observed, sectors 14 and 15, as was the case
with the Kepler observations. There is a tentative detection of the pulsation
mode at $1.37275\pm 0.00003$ mHz ($118.605\pm 0.003$ d -1) with an amplitude
of $0.17\pm 0.04$ mmag, as shown in Fig. 48. This tentative detection is
likely a result of the reduced sensitivity of the TESS data over Kepler data,
as discussed above. The spectral type of this star, F1 SrCrEu (Table 1), is
from Hey et al. (2019).

####  4.3.3 TIC 27395746

TIC 27395746 (KIC 11409673) is a further roAp star discovered by Hey et al.
(2019). This is another target that does not show the rotation or pulsation
signal as reported from the Kepler observations. However, with knowledge of
the rotation period, $P_{\rm rot}=1.06365\pm 0.00002$ d, from Hey et al.
(2019), we are able to conclude we detect a harmonic of the rotation frequency
of the star, but without that prior knowledge, would have dismissed the signal
as instrumental given both its low frequency and marginal significance, hence
we have not listed it in Table 1. The combination of the angles $i$ and
$\beta$ in this star result in a low amplitude mode with sidelobes of the
pulsation having higher amplitude. Therefore, we are unable to detect the
pulsation mode, but identified the $\nu-\nu_{\rm rot}$ sidelobe at a frequency
of $2.49995\pm 0.00003$ mHz ($215.996\pm 0.002$ d -1) with an amplitude of
$0.18\pm 0.04$ mmag, as shown in Fig. 49. The spectral type of this star, A9
SrEu (Table 1), is from Hey et al. (2019).

What is noted in the sector 14 and 15 light curve of TIC 27395746 is the
presence of eclipse signatures with a period of $10.27\pm 0.01$ d (Fig. 25)
which are not present in the Kepler data. Inspection of the target pixel file
(TPF) revealed a background eclipsing binary star included in the standard
photometric aperture. While this star does appear in many catalogues concerned
with eclipsing binary stars in the Kepler data (e.g., Conroy et al., 2014),
although those sources quote the rotation period as the orbital period and
have thus misclassified the star based on its surface spots.

Figure 25: Phase folded light curve of TIC 27395746 showing an eclipse-like
signature with a period of $10.27\pm 0.01$ d. The origin of the eclipse is
unclear.

####  4.3.4 TIC 77128654

TIC 77128654 (HD 97127) was discovered in SuperWASP data to be an roAp star
(Holdsworth et al., 2014a), and classified as an F3 SrEu(Cr). The amplitude
spectrum of the sector 22 data for this star does not show any signature of
rotation, but does reveal two significant pulsation frequencies (Fig. 50). The
dominant mode frequency agrees with that in the literature ($1.233855\pm
0.000004$ mHz; $106.6050\pm 0.0003$ d -1) while the second lower amplitude
mode at $1.248661\pm 0.000031$ mHz ($107.8843\pm 0.0027$ d -1) is newly
reported here. The separation of these two modes is $14.806\pm 0.003\,\mu$Hz
which is about one quarter of the expected large frequency separation for this
star.

####  4.3.5 TIC 123231021

TIC 123231021 (KIC 7582608) was discovered to be an roAp star through a search
of the SuperWASP photometric archive (Holdsworth et al., 2014a), and later
studied in detail by Holdsworth et al. (2014b). This star is known to show
significant frequency/phase variability in its sole pulsation mode (Holdsworth
et al., 2014b; Holdsworth, 2021) which makes precise determination of the
pulsation mode frequency difficult.

The TESS observations of this star, obtained in sectors 14 and 26, add no
additional information over that already presented in the literature (Fig.
51). Each individual sector of data spans just over one rotation cycle of the
star with the sectors separated by 300 d. This leads to a less precise, and
inaccurate, determination of the rotation period in the TESS data of
$19.805\pm 0.005$ d (compared to $20.4401\pm 0.0005$ d from Holdsworth et al.,
2014b). The TESS data also do not resolve the rotationally split sidelobes
observed in this star with Kepler data. Therefore, we refer the reader to
Holdsworth et al. (2014b) for a detailed discussion on this star. The spectral
type of this star, A7 EuCr (Table 1), is from Holdsworth et al. (2014a).

####  4.3.6 TIC 158216369

TIC 158216369 (KIC 7018170) is another roAp star identified by Hey et al.
(2019) in LC Kepler data. The sectors 14 and 26 data do not show signs of
variability due to spots (as was the case with the Kepler data) nor pulsation
(Fig. 52). Hey et al. (2019) suggested an intrinsic amplitude of 0.5 mmag for
the dominant mode in this star which is above the 0.28 mmag upper limit we
place on variability here. However, with the redder TESS bandpass, it is not
surprising that the mode is not detected above the noise here. The spectral
type of this star, F2 (SrCr)Eu (Table 1), is from Hey et al. (2019).

####  4.3.7 TIC 158271090

TIC 158271090 (KIC 10195926) was discovered to be an roAp star in the Kepler
field by Kurtz et al. (2011). TESS observed the star during sectors 14, 15 and
16. Analysis of the TESS light curve at low frequency allowed for the
determination of the rotation period to be $5.6845\pm 0.0002$ d which is in
agreement with that in the literature.

Kepler observations revealed two pulsation modes in this star, however the
TESS observations only showed the highest frequency mode (which also has the
highest amplitude) to be above the noise level (Fig. 53). The pulsation mode
detected in this star is similar to that in TIC 27395746 where the geometry
leads to higher amplitude sidelobes than the pulsation signal. Therefore, the
pulsation frequency listed in Table 1 is derived from the average of the
rotationally split sidelobes. The spectral type of this star, F0 Sr (Table 1),
is from Gray et al. (2016).

####  4.3.8 TIC 158275114

TIC 158275114 (KIC 8677585) was classified as an roAp star by Balona et al.
(2011a) from 10 d of commissioning data from Kepler. It was further studied by
Balona et al. (2013), with Holdsworth (2021) analysing all the Kepler data.
The Kepler data showed two low frequency modes with disputed origins, and many
modes in the typical range for roAp stars, all of which show frequency
variability. The TESS data analysed here, from sectors 14 and 26, do not show
the same low frequency variability as the Kepler data did, although the signal
in the Kepler data is significantly below the noise of the TESS data at the
same frequencies. There is a new ‘signal’ in the sector 14 data at a frequency
of $0.012$ mHz ($1.00$ d -1), however this is not present in the SPOC reduced
30-min cadence data for the same sector, nor the subsequent observations of
this star, so we class this as an instrumental (or pipeline) artefact.

We detected two pulsation modes in the combined data for this star,
significantly fewer than that seen in the Kepler data (Fig. 54). The two modes
were detected at $1.5853813\pm 0.0000009$ mHz ($136.97694\pm 0.00008$ d -1)
and $1.6217146\pm 0.0000019$ mHz ($140.11614\pm 0.00016$ d -1), where the
separation of the two modes is likely to be the large frequency separation, as
previously reported. In Table 1, the A5 p spectral classification is from
Macrae (1952).

####  4.3.9 TIC 159392323

TIC 159392323 (TYC 3547-2692-1) was classified as an roAp star by Holdsworth
(2015) through a survey of SuperWASP photometry, who also classified the star
as F3p SrEuCr. There have been no further studies of this star in the
literature. The TESS sector 15 data confirm the previous pulsation in this
star at a frequency of $1.49021\pm 0.00002$ mHz ($128.754\pm 0.001$ d -1), and
allowed for the detection of two new modes at $1.47658\pm 0.00005$ mHz
($127.576\pm 0.004$ d -1) and $1.49610\pm 0.00003$ mHz ($129.263\pm 0.003$ d
-1). As with the previous literature, we did not detect a rotation period for
this star.

Figure 26: Amplitude spectrum for TIC 159392323. The vertical dotted lines
identify the pulsation modes detected in the TESS data. The two lower
amplitude modes are newly detected.

####  4.3.10 TIC 169078762

TIC 169078762 (HD 225914) was listed in the Henry Draper Catalogue and
Extension (Cannon & Pickering, 1923) as an A7 spectral type star, but found to
be both chemically peculiar, A5Vp SrCr(Eu), and pulsating (in Kepler data) by
Smalley et al. (2015). They performed a detailed analysis of this object and
reported the pulsation mode at 0.7112 mHz (61.45 d -1) with an amplitude of
62.6 $\muup$mag using the 4-yr long Kepler photometry, and measured a precise
rotation period of $P_{\rm rot}=5.209358\pm 0.000009$ d.

The analysis of high-resolution spectra revealed the following stellar
parameters: $T_{\rm eff}=8100\pm 200$ K, $\log{g}=4.0\pm 0.2$ (cm s-2),
[Fe/H]=+0.31$\pm$0.24 and $v\sin i=14.6\pm 1.6$ km s-1(Smalley et al., 2015).
Line profile variations caused by rotation are also evident. Lines of Sr, Cr,
Eu, Mg and Si are strongest when the star is brightest (in the Kepler
bandpass), while Y and Ba vary in antiphase with the other elements. The
abundances of rare earth elements are only modestly enhanced compared to other
roAp stars of similar $T_{\rm eff}$ and $\log{g}$ (Smalley et al., 2015).

TESS observed the star in sector 14 at 2-min cadence. Both the previously
determined rotation period and pulsation frequency (Fig. 55) are confirmed in
these data.

####  4.3.11 TIC 171988782

TIC 171988782 (HD 258048) was first classified as an F8 star (Kharchenko,
2001) but Holdsworth et al. (2014a) showed it to be F4p EuCr(Sr) using low
resolution spectroscopy. They determined an effective temperate of $6200\pm
280$ K using the infrared flux method, and 6600 K from Balmer line fitting.
Holdsworth et al. (2014a) also classified the star to be an roAp star given
the presence of a significant peak in the amplitude spectrum of SuperWASP
photometry at $1.962$ mHz (169.54 d -1) with an amplitude of 1.49 mmag.
Jayasinghe et al. (2018) identified TIC 171988782 as a W UMa type binary based
on a period found in the ASAS-SN data. However, this period was not found in
the SuperWASP data, nor in the present TESS data.

TESS observed the star in sector 20 of Cycle 2. The principal mode identified
in the SuperWASP data is confirmed at $1.962238\pm 0.000005$ mHz ($169.5374\pm
0.0005$ d -1) with a new secondary mode found at $1.975095\pm 0.000023$ mHz
($170.6482\pm 0.0020$ d -1; Fig. 27). There is no indication of the rotation
period in this star.

Figure 27: Amplitude spectrum for TIC 171988782. The vertical dotted lines
identify the pulsation modes detected in the star.

####  4.3.12 TIC 264509538

TIC 264509538 (KIC 10685175) was discovered as an roAp star using super-
Nyquist analysis on Kepler Long Cadence (LC) data (Hey et al., 2019). That
work provided the first estimate for the principle pulsation frequency of
$2.783$ mHz ($240.45189$ d -1) as well as the rotation period of $P_{\rm
rot}=3.1020\pm 0.0001$ d. These values were reviewed by a new analysis based
on TESS data by Shi et al. (2020), where the fundamental pulsation mode and
rotational period were found to be 2.217 mHz ($191.5151$ d -1) and $3.1028\pm
0.0048$ d, respectively. In that work the star was found to be an oblique
quintuplet pulsator with sidelobes split by exactly the rotation frequency.
The discrepancy between the two pulsation frequencies is a result of the
incorrect selection of a Nyquist alias by Hey et al. (2019), an issue that is
discussed in their work.

Hey et al. (2019) obtained the effective temperature ($T_{\rm eff}=8000\pm
300$ K) from LAMOST spectra, and a luminosity (scaled with the solar
luminosity) of $\log L/{\rm L_{\odot}}=0.896\pm 0.022$ from Gaia DR2. A mass
of $M=1.65\pm 0.25$ M⊙ was also estimated through an interpolation over
stellar tracks based on the models of Cunha et al. (2013).

Since the TESS data, from sectors 14 and 15 (Fig. 56), have already been
analysed, we do not repeat the process here, but refer the reader to Shi et
al. (2020).

####  4.3.13 TIC 272598185

TIC 272598185 (KIC 10483436) was discovered to be an roAp star by Balona et
al. (2011b) through the analysis of Kepler Short Cadence data. In that work,
it was concluded that the star pulsates with a single mode at a frequency of
$1.35$ mHz (116.91 d -1) with an amplitude of $69\pm 2\,\muup$mag in the
Kepler passband, however the TESS data analysed here, from sectors 14 and 15,
showed no signs of variability with this frequency (Fig. 57) which is most
likely the result of the unfavourable longer wavelength observations of TESS.
The rotation period presented in Table 1 is more precise than that presented
by Balona et al. (2011b) since the combined TESS observations analysed here
have a longer baseline than the 27-d Kepler data set previously used.

####  4.3.14 TIC 273777265

TIC 273777265 (KIC 6631188) was discovered to be an roAp star by Hey et al.
(2019) through the analysis of Kepler LC data. The sector 14 and 15 TESS data
showed low frequency variability which is attributed to rotation of the star.
However, the derived rotation period is half of the value recorded in the
literature, suggesting we detected only a harmonic of the rotation period of
the star. The pulsation frequency found in the TESS data agreed with that in
the literature within 2.5 $\sigma$ ($1.49349\pm 0.00001$ mHz; $129.038\pm
0.001$ d -1; Fig. 58). Interestingly for this object, the amplitude presented
in Table 1 is larger than the predicted intrinsic amplitude in the Kepler
bandpass which is unexpected due to the redder wavelength coverage of TESS.
The spectral type of this star, F0 Sr (Table 1), is from Hey et al. (2019).

####  4.3.15 TIC 286992225

TIC 286992225 (TYC 2553-480-1) was discovered by Holdsworth et al. (2014a) in
SuperWASP data to be an roAp star. In that paper a single pulsation frequency
of $2.726$ mHz ($235.54$ d -1) was found, which is one of the highest
frequencies found for roAp stars. The authors classified the spectrum as A9p
SrEu, and they found an effective temperature ranging from $7100\pm 200$ K
(from Balmer lines) to $7500\pm 400$ K (from SED analysis). Moreover analysis
of the H$\alpha$ profile seemed to indicate the presence of a core-wing
anomaly (e.g., Cowley et al., 2001).

An analysis of TESS data for this star was presented by Mathys et al. (2022).
The data show two modes separated by $35\,\muup$Hz, which the authors deduced
that to be half of the large separation. TIC 286992225 is also classified as a
super-slowly rotating Ap (ssrAp) star, i.e., an Ap star with a rotation period
greater than 50 d.

We add no further analysis for this star with the TESS data (sector 23; Fig.
59), so refer the reader to Mathys et al. (2022) for full details.

####  4.3.16 TIC 302602874

TIC 302602874 (TYC 2488-1241-1) was, upon its discovery as a variable star,
classified as A6p SrEu (Holdsworth et al., 2014a). The authors found $T_{\rm
eff}$ to be 7800 $\pm$ 200 K (from Balmer lines) and 8300 $\pm$ 500 K (from
SED fitting). The latter estimate is in line with $T_{\rm eff}=8200$ K
provided in the TIC.

This star was the subject of its own study in Holdsworth et al. (2018c), in
which the pulsation mode was concluded to be a distorted quadrupole mode. The
TESS data analysed here (from sector 21; Fig 60) add no further information
for this star; we refer the reader to Holdsworth et al. (2018c) for full
details.

##  5 Candidate roAp stars

In this section, we provide information on a number of stars that were flagged
by the search teams as possible roAp stars. These stars are classed as
candidate roAp stars since a combination of their spectral classification not
indicating chemical peculiarity, their light curve does not show $\alpha^{2}$
CVn rotational variability, their pulsation signature does not show signs of
multiplets split by the rotation frequency, their presumed pulsation signal is
close to a signal to noise limit of 4.0, or there is indiction they are a
member of a binary system. The stars listed in this section would benefit from
high-resolution spectroscopy to search for peculiarities and a magnetic field.

###  5.1 TIC 9171107

TIC 9171107 (TYC 2479-429-1) has limited information available in the
literature. The TIC gives an effective temperature of 6800 K and $\log g$ of
4.2 (cm s-2) while Gaia EDR3 gives $T_{\rm eff}=6800\,K$ and $\log g$ of 3.7
(cm s-2) (Gaia Collaboration, 2020). No pulsation detections have been
reported.

TIC 9171107 was observed in TESS sector 20 and showed no sign of rotation in
its light curve. However, there are three significant short period signals in
the amplitude spectrum of the light curve that we attribute to pulsation:
$1.50971\pm 0.00004$ mHz ($130.439\pm 0.003$ d -1), $1.52902\pm 0.00002$ mHz
($132.107\pm 0.002$ d -1) and $1.53502\pm 0.00002$ mHz ($132.625\pm 0.002$ d
-1; Fig. 28). The two lowest frequency modes are separated by 19.3 $\muup$Hz,
while the two highest frequency modes are separated by 6.0 $\muup$Hz. The
former separation may be half of the large frequency separation, while the
latter separation may be the small frequency separation777defined as the
difference between two odd or even degree modes that have a radial overtone
difference of one.

There are no spectroscopic data of this object in the literature, and no
Strömgren-Crawford indices that are available to classify the star as
chemically peculiar. Therefore, we placed this star as a candidate roAp star
until such data are available.

Figure 28: Amplitude spectrum of TIC 9171107, with the pulsation modes
indicated with the vertical dotted lines.

###  5.2 TIC 275642037

TIC 275642037 (TYC 4330-716-1), has no published spectral type. However, from
photometry Ofek (2008) and Pickles & Depagne (2010) both infer F0 V. The TIC
gives $T_{\rm eff}=7700\pm 400$ K, while 7200 K was obtained by McDonald et
al. (2017) and 7550 K by Ammons et al. (2006). The Gaia DR3 flags this star as
photometrically variable as "DSCT|GDOR|SXPHE", with a $g$-band amplitude of
5.9 mmag at a single frequency of $8.1\,\muup$Hz (0.6965 d -1, 1.436 d). Gaia
DR3 data also showed a variable radial velocity of $4.56\pm 0.84$ km s-1, with
an amplitude of 10.67 km s-1and a spectral broadening of $44\pm 10$ km s-1,
which is a proxy for $v\sin i$ (Frémat et al., 2023). There is no mention of
any chemical peculiarities, rotational variability or pulsations in the
literature.

TESS observed this star during sector 18. There is clear low-frequency
variability in the TESS light curve of this star that could either be
attributed to rotation in the presence of stable spots, or an orbiting
companion. The Gaia DR3 low-frequency result is half of the period we detected
here ($P_{\rm rot}=2.8745\pm 0.0003$ d; Fig.29), which is the dominant signal
in an amplitude spectrum. The pulsations we detected (Fig. 30) at frequencies
of $1.13943\pm 0.00003$ mHz ($98.447\pm 0.003$ d -1) and $1.16939\pm 0.00002$
mHz ($101.035\pm 0.001$ d -1) are stable in both amplitude and phase over the
observation period. They are also separated by 30 $\mu$Hz, which could
plausibly be half the large separation. Given the lack of rotational sidelobes
to the pulsations, and confirmation that this is an Ap star, it remains a
candidate roAp star until it is spectroscopically observed to determine any
chemical peculiarity.

Figure 29: Phase folded light curve of TIC 275642037, phased on a period of
$2.8745\pm 0.0003$ d. The data are binned 50:1 Figure 30: Amplitude spectrum
of TIC 275642037 showing the pulsation modes (marked by the vertical dotted
lines).

###  5.3 TIC 298052991

TIC 298052991 (TYC 4554-625-1) has been classified as an A2 star by Kervella
et al. (2019). The same authors also performed an analysis to characterise the
presence of a stellar/substellar mass around the star and found a physical
companion orbiting it. They gave the mass, assuming a semi-major axis of 1 au
as $M_{2}=12_{-5}^{+6}$ MJup, using a primary mass and radius of
$M_{1}=1.60\pm 0.08$ M⊙ (Girardi et al., 2000) and $R_{1}=1.50\pm 0.08$ R⊙
(Kervella et al., 2004). McDonald et al. (2012) derived the stellar
temperature and luminosity to be $T_{\rm{eff}}=9550$ K and $L=9.6$ L⊙,
respectively, from the comparison of the $\chi^{2}$ statistic between observed
photometric data and a set of synthetic stellar spectra. Balona (2022)
presented an analysis of the TESS data from sectors 14, 20, 21, 26, 40 and 41
and found a rotation period of $10.638$ d and a pulsation frequency of $2.291$
mHz (197.951 d -1).

During Cycle 2, TIC 298052991 was observed during sectors 14, 20, 21 and 26.
For this star, we used the SAP data to derive the rotation period as the
signal in the PDC data had been altered by the processing. We derived a period
of $10.5852\pm 0.0001$ d (Fig. 31), which significantly differs from that
previously determined given the use of the SAP data here. To investigate the
pulsations, we pre-whitened the individual sectors to remove peaks below
$0.116$ mHz (10 d -1) to the noise level of the high-frequency range. This
allowed us to detect three pulsation frequencies in this star (Fig. 32;
$2.217569\pm 0.000003$ mHz, $191.5979\pm 0.0002$ d -1; $2.246466\pm 0.000002$
mHz, $194.0947\pm 0.0001$ d -1; $2.291038\pm 0.000001$ mHz, $197.9457\pm
0.0001$ d -1), with a tentative detection of a fourth signal ($2.185497\pm
0.000003$ mHz, $188.8270\pm 0.0003$ d -1).

Figure 31: Phase folded SAP light curve of TIC 298052991, phased on a period
of $10.5852\pm 0.0001$ d. The data are binned 200:1 Figure 32: Amplitude
spectrum of TIC 298052991 showing the pulsation modes (marked by the vertical
dotted lines).

Since there is no evidence of chemical peculiarities or rotational splitting
of modes, we are unable to confirm if this star is a bona fide roAp star, thus
it remains a candidate for now.

###  5.4 TIC 405892692

TIC 405892692 (BD+49 3179) is a little-studied star. Hill & Schilt (1952)
classified this $V=9.28$ mag star as F0. The TIC catalogue (Stassun et al.,
2019) lists the atmospheric parameters $T_{\rm eff}=7250$ K and $\log g=4.24$
(cm s-2), however there are no indications of chemical peculiarity for this
star. Balona (2022) claimed the star to be a rotational variable with a
pulsation at high frequency, based on TESS observations.

This star was observed in sectors 14 and 15. We detected a low frequency peak
of uncertain origin in the amplitude spectrum, corresponding to a period of
$P=0.3786\pm 0.0001$ d. This is a short rotation period for an F0 star, so we
postulated that this is in fact a signature of a binary, or higher order,
system. This is tentatively supported by the Gaia DR3 binary probability flag
being essentially unity (Gaia Collaboration, 2022). The pulsation signature we
detected is at a frequency of $1.17082\pm 0.00002$ mHz ($101.159\pm 0.001$ d
-1; Fig. 33), which agrees with that previously reported.

Figure 33: Amplitude spectrum of TIC 405892692 showing the detection of a
pulsation mode (marked by the vertical dotted line).

Since there is little information available on this star, and the lack of any
convincing evidence that it is chemically peculiar, this remains a candidate
roAp star.

###  5.5 TIC 429251527

TIC 429251527 (TYC 2185-478-1) is another star with very little information in
the literature. This $V=10.5$ mag star has no spectral classification or any
other dedicated studies available. The atmospheric parameters, $T_{\rm
eff}=7900$ K and $\log g=4.66$ (cm s-2), are provided in the TIC (Stassun et
al., 2019), while the Gaia DR3 data suggested a compatible value of $T_{\rm
eff}=7950$ K. The TIC $\log g$ value is anomalously high, with Gaia D3
providing a more likely value of $\log g=3.99$ (cm s-2).

TESS observed the star in sector 15. The data did not show any rotation
signature, but did show a pulsation with significant amplitude at $1.77798\pm
0.00001$ mHz ($153.6178\pm 0.0008$ d -1; Fig. 34). This is the first report of
the pulsation in this star. Given the presence of only one mode, which does
not show rotational splitting, and the lack of information in the literature,
we cannot confirm this star to be an roAp star, and thus leave this as a
candidate for now.

Figure 34: Amplitude spectrum of TIC 429251527 showing the pulsation mode
marked by the vertical dotted line.

###  5.6 TIC 445796153

TIC 445796153 (HD 34740) has several spectral classifications in the
literature: Am (A3-A7) (Bertaud & Floquet, 1967); A0p or A2V (Percy, 1975);
A0p (Cannon & Pickering, 1918b). However, the peculiarity was marked as
doubtful by Renson & Manfroid (2009). The estimated effective temperature from
Gaia DR3 is $T_{\rm eff}=10500$ K (Gaia Collaboration, 2022), this, coupled
with the spectral classifications, places this star at the hot end of the roAp
range. Hauck & Mermilliod (1998) measured Strömgren-Crawford indices of this
star to be: $b-y=0.073$, $m_{1}=0.201$, $c_{1}=0.937$ and H$\beta=2.817$,
giving $\delta m_{1}=0.005$ and $\delta c_{1}=0.127$. However, there is
disparity between the measured H$\beta$ and $b-y$ values, with the former
giving an equivalent $b-y$ of 0.129, redder than the observed value. The star
is listed as a multiple system (Mason et al., 2001) with a $\delta m_{v}=2.96$
mag, which, based on the Gaia $T_{\rm eff}$ suggests a late B star with an
early F companion. This may explain the discrepancies in the indices. The TESS
data for TIC 445796153 were analysed by Balona (2022) to label the star as a
possible $\alpha^{2}$ CVn star (with a period of $P_{\rm rot}=5.576$ d) with
high-frequency $\delta$ Sct modes.

Here, we used the TESS sector 19 and 26 data to confirm the rotation period of
$P_{\rm rot}=5.5721\pm 0.0004$ d (Fig. 35). We also detected two pulsation
modes (Fig. 36) that are in the frequency range where both $\delta$ Sct and
roAp pulsation modes can be found (e.g., TIC 356088697, $0.646584\pm 0.000008$
mHz; Paper I): $0.601908\pm 0.000002$ mHz ($52.0049\pm 0.0002$ d -1) and
$0.675849\,0.000002$ mHz ($58.3934\,0.0001$ d -1). It is unusual for a
$\delta$ Sct star to exhibit so few modes, especially at this amplitude.
However, we cannot rule out the possibility that these modes are indeed
$\delta$ Sct in nature, as that requires an investigation into the pulsation
driving which differs between the two classes and is beyond the scope of this
work. We therefore class TIC 445796153 as a candidate roAp star, especially
given the lack of convincing spectral classification of the star being
chemically peculiar. Spectroscopic monitoring to provide a binary solution,
coupled with time-resolved spectra will help identify the origin of the
pulsations in this binary system. Efforts should also be made to exclude the
possibility of a contaminating $\delta$ Sct star.

Figure 35: Phase folded light curve of TIC 445796153, phased on a period of
$5.5721\pm 0.0004$ d. The data are binned 200:1 Figure 36: Amplitude spectrum
of TIC 445796153. The two pulsation modes marked with vertical dotted lines.

###  5.7 TIC 91224991

TIC 91224991 (HD 191380) has a spectral classification in the literature of F8
(Cannon & Pickering, 1923). Stassun et al. (2019) estimate the effective
temperature and $\log g$ to be 6700 K and 3.97 (cm s-2), respectively. The
effective temperature is determined from the dereddened Bp-Rp colour, while
the $\log g$ value is derived using the estimated mass and radius. Another
estimation of $T_{\rm eff}$ is given by Ammons et al. (2006) as 6650 K, while
Anders et al. (2019) derived $T_{\rm eff}$ = 6960 K based on narrow-band
photometry.

Balona (2022) categorised this star as an A star with high frequency
variability, based on the TESS data. He estimated a luminosity $\log L/{\rm
L}_{\odot}=0.96$ using Gaia EDR3 parallaxes (Gaia Collaboration et al., 2016,
2021) in conjunction with interstellar reddening corrections from Gontcharov
(2017) and a bolometric correction calibration by Pecaut & Mamajek (2013).
Balona (2022) found a characteristic frequency $1.160$ mHz (100.213 d -1) and
also one harmonic, but does not give a rotation frequency. This star was also
observed using long baseline interferometry by Cruzalèbes et al. (2019), who
found an angular diameter corresponding to a radius of $R=2.13$ R⊙.

This star was added to the TESS 2-min target list as a result of a tentative
detection of variability in KELT data (Pepper et al., 2007) that was made
available to the TASOC WG4 members. The TESS data, from sector 14, clearly
showed the presence of high frequency variability. We determined the frequency
to be $1.159876\pm 0.000002$ mHz ($100.2133\pm 0.0002$ d -1; Fig. 37), and
note the presence of the second harmonic at twice this frequency. Our results
are consistent with those of Balona (2022). There are no rotational sidelobes
to the pulsation peak in the amplitude spectrum, which is expected given the
lack of a rotation signal in the TESS data.

Figure 37: Amplitude spectrum of TIC 91224991. The vertical dotted line marks
the pulsation mode.

##  6 The remaining roAp stars

To provide a complete sample of roAp stars, we must include those that have
not been observed by TESS and those that have been observed or discovered
beyond the Cycle 1 and Cycle 2 observations. Therefore, in Table 3 we present
these stars. Where there are now TESS data available, we follow the procedures
outlined above to provide the rotation and pulsation properties. For each
star, we present their amplitude spectrum in the range of the pulsations in
Appendix D, and for stars that have yet to be observed, we provide the
literature information.

Table 3: Details of the roAp stars not observed in Cycles 1 or 2. The columns provide the TIC identifier and star name, the TIC v8.1 TESS magnitude, the spectral type, the effective temperature, as provided in the TIC, the sectors in which TESS observed the target, where applicable. The final three columns provide the stellar rotation period derived in this work, the pulsation frequency(ies) (note that sidelobes that arise from oblique pulsation are not listed), and the pulsation amplitude(s) seen in the TESS data. A ‘*’ indicates excess power remains in the amplitude spectrum after extracting the modes listed. Frequencies marked with a † are derived from sidelobes. A ${\ddagger}$ denotes that the SAP data were used to derive the value. For the stars not observed by TESS the superscript after the TIC ID give the data reference, and we neglect providing the amplitude since various different techniques and/or filters were used, thus making them non-comparable to the TESS results. TIC | HD/TYC | TESS | Spectral | $T_{\rm eff}^{\rm TIC}$ | Sectors | $P_{\rm rot}$ | Pulsation frequency | Pulsation amplitude
---|---|---|---|---|---|---|---|---
| name | mag | type | (K) |  | (d) | (mHz) | (mmag)
roAp stars discovered in TESS data |  |  |
33604636 | 42605 | 8.78 | Ap SrEuCr | 8280 | 33 | $2.7793\pm 0.0011$ |  $1.25733\pm 0.00002$* | $0.068\pm 0.007$
36576010 | 216018 | 7.45 | A9Vp SrCrEu | 7750 | 42 | No signaturea | $1.92919\pm 0.00003$ | $0.045\pm 0.006$
198781841 | 2134-154-1 | 10.58 | – | 7730 | 40,53,54 | No signature | $1.8913785\pm 0.0000005$ | $0.25\pm 0.01$
|  |  |  |  |  |  | $1.9271666\pm 0.0000003$ | $0.40\pm 0.01$
|  |  |  |  |  |  | $1.9629854\pm 0.0000009$ | $0.15\pm 0.01$
229960986 | 4221-240-1 | 10.38 | – | 8150 | 40,41,47-55 | $2.093996\pm 0.000003$ | $2.2179825\pm 0.0000009$ | $0.082\pm 0.006$
453826702 | 22032 | 8.81 | Ap SrEuCr | 8100 | 31 | $4.8525\pm 0.0007$ |  $1.57518\pm 0.00003$* | $0.051\pm 0.007$
|  |  |  |  |  |  | $1.60998\pm 0.00001$ | $0.131\pm 0.007$
|  |  |  |  |  |  | $1.64107\pm 0.00003$ | $0.061\pm 0.007$
456673854 | 59702 | 8.56 | A8V | 7770 | 34 | $5.438\pm 0.001$ | $3.13157\pm 0.00004^{\dagger}$ | <0.03
|  |  |  |  |  |  | $3.16928\pm 0.00002$ | $0.113\pm 0.008$
|  |  |  |  |  |  | $3.20693\pm 0.00004^{\dagger}$ | <0.02
630844439 | 9348-1029-1 | 8.44 | A8m |  | 27,28 | $1.6618\pm 0.0003$ | $3.36021\pm 0.00001$ | $0.13\pm 0.01$
Known roAp stars prior to TESS launch |  |  |
96855460 | 185256 | 9.55 | Fp SrEu | 7100 | 27 | $\sim 24$ | $1.62766\pm 0.00003$ | $0.13\pm 0.01$
100196783 | 193756 | 8.98 | Ap SrCrEu | 7590 | 67 | $3.0096\pm 0.0005$ | $1.28405\pm 0.00001$ | $0.199\pm 0.008$
163587609 | 101065 | 7.53 | F8/G0p | 6125 | 37 | No signaturea | $1.315020\pm 0.000017$ | $0.065\pm 0.005$
|  |  |  |  |  |  | $1.369901\pm 0.000010$ | $0.116\pm 0.005$
|  |  |  |  |  |  |  $1.372881\pm 0.000001$* | $0.958\pm 0.005$
|  |  |  |  |  |  | $1.393128\pm 0.000010$ | $0.112\pm 0.005$
|  |  |  |  |  |  | $1.427743\pm 0.000039$ | $0.028\pm 0.005$
293265536 | 4-562-1 | 9.93 | A9p SrEu(Cr) | 7640 | 42 | No signature | $1.73910\pm 0.00001$ | $0.32\pm 0.01$
299000970 | 176232 | 5.69 | A7p ArEu | 7520 | 53,54 | No signaturea | $1.336785\pm 0.000013$ | $0.012\pm 0.001$
|  |  |  |  |  |  | $1.396832\pm 0.000003$ | $0.045\pm 0.001$
|  |  |  |  |  |  | $1.417638\pm 0.000018$ | $0.009\pm 0.001$
|  |  |  |  |  |  | $1.427100\pm 0.000005$ | $0.029\pm 0.001$
|  |  |  |  |  |  | $1.447892\pm 0.000006$ | $0.027\pm 0.001$
|  |  |  |  |  |  | $1.508482\pm 0.000024$ | $0.006\pm 0.001$
318007796 | 190290 | 9.61 | Ap EuSr | 7560 | 27,39 | $4.09070\pm 0.00002$ | $2.2307867\pm 0.0000015$ | $0.049\pm 0.007$
|  |  |  |  |  |  | $2.2723808\pm 0.0000002$ | $0.307\pm 0.007$
354619745‡ | 201601 | 4.48 | A9Vp SrCrEu | 7490 | 55 | No signaturea | $1.311230\pm 0.000009$ | $0.044\pm 0.002$
|  |  |  |  |  |  | $1.338619\pm 0.000001*$ | $0.317\pm 0.002$
|  |  |  |  |  |  | $1.366022\pm 0.000003$ | $0.124\pm 0.002$
383521659${\ddagger}$ | 137909 | 3.40 | F2Vp SrEuSi |  | 51 | $\sim 18.3$ | No signal in TESS data | < 0.005
407929868${\ddagger}$ | 24355 | 9.43 | A7/F0 | 7830 | 42,43,44 | $27.724\pm 0.008$ | $2.5961335\pm 0.0000003$ | $2.056\pm 0.006$
420687462 | 122970 | 7.93 | F0 | 6800 | 50 | No signature | $1.476848\pm 0.000035$ | $0.053\pm 0.007$
|  |  |  |  |  |  | $1.477817\pm 0.000015$ | $0.120\pm 0.007$
|  |  |  |  |  |  | $1.502519\pm 0.000005$ | $0.290\pm 0.006$
445543326 | 12098 | 7.91 | F0 Eu | 7760 | 58 | $5.4816\pm 0.0008$ | $2.12206\pm 0.00003$ | $0.062\pm 0.007$
|  |  |  |  |  |  | $2.12636\pm 0.00004$ | $0.040\pm 0.007$
|  |  |  |  |  |  | $2.30602\pm 0.00003$ | $0.054\pm 0.007$
Known roAp stars not observed by TESS |  |  |
153101639b | – | 11.87 | A7Vp SrEu(Cr) | 7510 |  | $3.6747\pm 0.0005$ | $1.7585027\pm 0.0000002$ |
335303863c | 137949 | 6.45 | F0Vp EuGdSr | 7400 |  | >10 000d | $2.01475317\pm 0.00000007$ |
411247704e | 196470 | 9.49 | Fp SrEu | 7450 |  | None published | $1.544$ |
413938178f | 148593 | 8.71 | Ap SrEuCr | 7390 |  | None published | $1.56\pm 0.01$ |
432223926g | 134214 | 7.17 | F2Vp SrCrEu | 7040 |  | None published | $2.9496\pm 0.0004$ |
465996299h | 177765 | 8.87 | Ap SrEuCr | 7420 |  | >13 500 | $0.702580\pm 0.000006$ |
|  |  |  |  |  |  | $0.713382\pm 0.000015$ |
|  |  |  |  |  |  | $0.717106\pm 0.000010$ |
aSee text for rotation period discussion. bHoldsworth et al. (2018b);
cHoldsworth et al. (2018d); dGiarrusso et al. (2022); eMartinez et al. (1990)
fKochukhov et al. (2013); gKreidl et al. (1994); hHoldsworth (2016)

After accounting for the stars already presented as roAp stars in Paper I,
this work, and that of Jayaraman et al. (2021) who reported TIC 198781841 and
TIC 229960986 to be roAp stars, there are 27 additional stars listed in Balona
(2022) as roAp stars, or candidate roAp stars. Of these 27, 11 appeared in
Holdsworth et al. (2014a) as either Am or marginal Am (Am:) stars. Four of
these 11 stars have no TESS 2-min cadence data so it is unclear how Balona
(2022) decided a different variability type than the original classification,
four further stars showed clear $\delta$ Sct pulsations and one is a known
binary with a compact pulsator. Of the two final Am(:) stars, TIC 22113439 is
listed as a double lined spectroscopic binary in LAMOST DR9 data (Zheng et
al., 2023) which explained the low frequency variability combined with the
$\delta$ Sct pulsations, and careful examination of the light curve of TIC
22132451 showed that the low-frequency variability changed phase over the
observations (sectors 40, 52 and 53), which is not expected of an $\alpha^{2}$
CVn variable. This, coupled with the pulsations being of a $\delta$ Sct
nature, means we rejected this as an roAp star.

Beyond the Am(:) stars, we considered TIC 427400331. This star is listed as a
Be star by Labadie-Bartz et al. (2022) who commented on the presence of Slowly
Pulsating B (SPB) star g-modes, and noted the unusual presence of high-
frequency variability. We checked the high-frequency modes and found they did
not show oblique pulsation, despite a confirmed rotation period. Two low
resolution spectra, in the Be Star Spectra (BeSS) database did not show strong
absorption lines typical of Ap stars, and the Gaia DR3 Re-normalised Unit
Weight Error (RUWE) value is >25, strongly indicating a binary star. We
therefore rejected this star as an roAp star, pending an investigation to the
source of the high-frequency variability. We rejected a further eight stars on
the grounds of either them being obvious $\delta$ Sct stars or having no
signal at the claimed frequency. Finally, two stars of the 27 roAp stars in
Balona (2022) are listed as candidates in our work (TIC 410163387 in Paper I,
and TIC 405892692 here). Given there are no additional data products
available, we did not include these stars as roAp in Table 3. The five
remaining stars are included as roAp stars in Table 3.

In other work, Mathys et al. (2020) and Mathys et al. (2022) noted 10
candidate roAp stars that were detected as part of a systematic search of the
TESS data for ssrAp stars. Nine stars, one of which is the same as a candidate
in Balona (2022), are rejected as roAp stars here due to the lack of a
detection of an appropriate peak in the amplitude spectra. One star, TIC
72802368 from Mathys et al. (2020), remains a candidate as a signal at the
reported frequency ($1.207677\pm 0.000001$ mHz) is detected in two (sectors 36
and 62) of the three available sectors.

Below, we provide comments on all stars in Table 3 with TESS data:

  * •

TIC 33604636 (HD 42605) – There are clear signs of residual power in the
amplitude spectrum after the removal of the pulsation frequency. It is not
clear if there are further modes present, or amplitude/frequency variability
at play (cf. Fig 61).

  * •

TIC 36576010 (HD 216018) – There may be additional modes around 1.79 mHz that
are not fully resolved (cf. Fig 62). The rotation period is disputed in the
literature, see Mathys et al., (submitted) for a discussion.

  * •

TIC 198781841 (TYC 2134-154-1) – The modes in this star are split by
$\sim\,35.8\,\muup$Hz, which is plausibly half the large frequency separation
(see Jayaraman et al., 2021) (cf. Fig 63).

  * •

TIC 229960986 (TYC 4221-240-1) – Application of the oblique pulsator model for
this star resulted in a $\tan i\tan\beta$ value of $6.10\pm 0.43$, and the
conclusion that the mode is a slightly distorted dipole mode due to unequal
phases between the pulsation mode and the sidelobes (cf. Fig 64).

  * •

TIC 453826702 (HD 22032) – The three modes identified in this star are
separated by an average of $\sim 33\,\muup$Hz which is plausibly half of the
large frequency separation for this star. After removing the three identified
modes, there remains excess power of unknown origin in the same frequency
range (cf. Fig 65).

  * •

TIC 456673854 (HD 59702) – The amplitude spectrum of this star showed, in
increasing frequency, a dipole mode, a quadrupole mode and another dipole
mode. The dipole modes form doublets with only the sidelobes visible while the
quadrupole mode showed the pulsation and the $\pm 2\nu_{\rm rot}$ sidelobes.
With the application of the oblique pulsator model, we found that all three
modes have $\tan i\tan\beta$ in agreement ($7.57\pm 3.38$ for the first
dipole, $10.91\pm 3.84$ for the quadrupole, and $5.29\pm 2.57$ for the second
dipole), with the phase relations suggesting the first two modes are non-
distorted, while the second dipole mode is suggested to be a distorted mode.
This star will benefit from an in-depth study (cf. Fig 66).

  * •

TIC 630844439 (TYC 9348-1029-1) – The amplitude spectrum of this star showed
the presence of both rotation and g-mode pulsations. It is noted in the
literature as a binary star, so we postulate that the g-modes are from a
$\gamma$ Dor companion to an roAp star. The high-frequency peaks form a
triplet, suggesting a single dipole mode in the roAp star. Applying the
oblique pulsator model to the triplet resulted in $\tan i\tan\beta=2.48\pm
0.27$, and the indication that the mode is slightly distorted (cf. Fig 67).

  * •

TIC 96855460 (HD 185256) – The SAP data were used for this star to provide a
lower limit on the rotation period. No new information is gleaned about the
pulsation mode (cf. Fig 68).

  * •

TIC 100196783 (HD 193756) – This star showed strong g-mode pulsation
superimposed on the rotation signature. This is the first time this is
mentioned in the literature. While there is no confirmation that this star is
a binary, the Gaia RUWE ($\approx 3.6$) suggests otherwise. The TESS data
provide no new information on the roAp pulsation (cf. Fig 69).

  * •

TIC 163587609 (HD 101065) – While there are five pulsation modes detected in
the star, there is no clear indication of the large frequency separation.
Three modes are separated by $\sim 55\,\muup$Hz, but this value is in
disagreement with $64\,\muup$Hz from Mkrtichian et al. (2008). It is unclear
which, if either, of these large separation values is correct. There is also
excess power remaining in the amplitude spectrum around the principal peak
after it was removed (cf. Fig 70). This star has a lower limit on its rotation
period of $\sim 43$ yr (Hubrig et al., 2018).

  * •

TIC 293265536 (TYC 4-562-1) – No new information is provided by the TESS data
(cf. Fig 71).

  * •

TIC 299000970 (HD 176232) – With the identification of six pulsation modes, we
were able to identify two recurrent separations of $\sim 60\,\muup$Hz and
$\sim 30\,\muup$Hz, which we interpreted as the large frequency separation,
and half of it. This is different from the value adopted by Huber et al.
(2008) of $50\,\muup$Hz, based on MOST photometry (cf. Fig 72). Sikora et al.
(2019b) propose a rotation period much greater than 12 yr.

  * •

TIC 318007796 (HD 190290) – The TESS data showed both modes in this star to be
multiplets thus allowing for the determination that the lowest frequency mode
is a dipole mode, with the other being a quadrupole mode, which suggests a
large frequency separation of $\sim 83\,\muup$Hz. Applying the oblique
pulsator model resulted in $\tan i\tan\beta$ values for the dipole and
quadrupole of $4.01\pm 0.61$ and $3.51\pm 0.27$, respectively, with the phase
variations relations for each mode suggesting they are both distorted (cf. Fig
73).

  * •

TIC 354619745 (HD 201601) – We list three pulsation modes in this star, but
note there is residual power remaining in the amplitude spectrum after they
are removed. The three modes are each separated by $27.4\,\muup$Hz, which is
presumably half of the large frequency separation. The principal mode showed a
harmonic at twice its frequency, which is joined by a second peak whose
frequency is the sum of the two highest amplitude modes. This non-linear
interaction is only the third occurrence noted in the literature after 33 Lib
(Holdsworth et al., 2018d) and $\alpha$ Cir Paper I (cf. Fig 74). The rotation
period of this star is expected to be of order $100$ yr (Bychkov et al.,
2016).

  * •

TIC 383521659 (HD 137909) – We did not detect the pulsation mode in this star
in the TESS data. The pulsation was detected spectroscopically with an
amplitude of about $30$ m s-1 (Kurtz et al., 2007), and is suspected to be
below the TESS noise level (cf. Fig 75).

  * •

TIC 407929868 (HD 24355) – The TESS data of this star showed a highly
distorted quadrupole mode, but did not add additional information over the
literature (cf. Fig 76).

  * •

TIC 420687462 (HD 122970) – The TESS data do not add new information to the
literature for this star (cf. Fig 77).

  * •

TIC 445543326 (HD 12098) – This star showed a dipole triplet with a second