in the Solar neighborhood allows spectroscopic follow-up of high spectral resolution and/or on small telescopes, and easy detection of low-mass members, making them particularly valuable.

For almost a century, the Scorpius-Centaurus OB-association (Sco-Cen) has been known as an ensemble of young, massive early-type stars, and which should hold the keys of star formation. divided the huge nearby association into three subgroups, Upper Scorpius (US), Upper Centaurus Lupus (UCL) and Lower Centaurus Crux (LCC). Being on the southern hemisphere the quality of the astrometric data historically was always poorer than for associations on the northern hemisphere. Only with the advent of the Hipparcos data the situation changed, but only for a subset of the brightest stars. In their fundamental paper, using the Hipparcos measurements, @1999AJ....117..354D presented an overview of the OB-associations in the wider neighborhood of the Sun. For Scorpius-Centaurus they obtained mean distances of 145 pc for US, 140 pc for UCL and 118 pc for LCC. @2016MNRAS.461..794P determined median ages of 11 (US), 16 (UCL), and 17Myr (LCC), though each has a considerable spread of ages. Other authors obtained ages as low as 5Myr for US [@Preib99; @Preib08], and 16 (UCL) to18 Myr (LCC) [@Sarto03; @Mamaj02].

In their introduction 