for variations of the actual instrumental parameters $w$ and $T$, which are already accounted for. After examining a large number of possible combinations, we adopt the parameters expressed in Equation \[eq:mcmc photometry\].

To derive the star and planet parameters, we run 5 MCMC chains of $10^5$ iterations and merge their posterior probability distributions. The results are reported in Table \[tab:final param mcmc\]. The best fit model yields a point-to-point precision of 366 ppm (Figure \[fig:white-light curve\]). The Poisson noise limit is 203 ppm per exposure. The minimum $\chi^2$ is 716 for 719 degrees of freedom, indicating uncertainties are well estimated.

  Instrumental parameters                            Precision (ppm)
  ------------------------------------------------- -----------------
  None                                                    2790
  $F_0$                                                    625
  $F_0$, $\alpha$                                          560
  $F_0$, $\alpha$, $x$, $y$                                423
  $F_0$, $\alpha$, $x$, $y$, $w$, $T$                      409
  $F_0$, $\alpha$, $x$, $y$, $w$, $T$, $\alpha^2$          367
  \[tab:parameter combinations\]                    

  : Examples of white-light curve precision after decorrelation from different instrumental parameter combinations.

          Parameter                  Units                 Value                        
  -------------------------- --------------------- ---------------------- ------------- -------------
             $P$                   \[days\]         2.61586178$^\dagger$                
         $M_{\star}$          \[$\rm M_{\odot}$\]      0.971$^\ddag$                    
         $R_{\star}$          \[$\rm R_{\odot}$\]          0.990            $-$ 0.009     $+$ 0.009
       $R_p/R_{\star}$                                    0.10304          $-$ 0.00037   $+$ 0.00037
            $t_1$                   \[HJD\]            2454406.71987       $-$ 0.00016   $+$ 0.00017
            $t_2$                   \[HJD\]            2454445.95817       $-$ 0.00016   $+$ 0.00019
            $t_3$                   \[HJD\]            2454508.73829       $-$ 0.00016   $+$ 0.00014
         $\tau_{14}$               \[hours\]               