Empirical Limb-darkening Coefficients and Transit Parameters of Known Exoplanets from TESS

Abstract Although the main goal of Transiting Exoplanet Survey Satellite (TESS) is to search for new transiting exoplanets, its data can also be used study already-known systems in further detail. The TESS bandpass particularly interesting limb-darkening effect stellar host that imprinted transit light curves, as widely phoenix and atlas models predict different profiles. Here we this by fitting curves 176 known exoplanetary observed TESS, which allows us extract empirical coefficients (LDCs) quadratic law but updated parameters (including ephemeride refinements) a by-product. Comparing our empirically obtained LDCs with theoretical predictions, find significant offsets when using tabulated LDCs. Specifically, u 2 show largest discrepancies depending on method derive them, reach up ? ? 0.2, average. Most those average disappear, however, if one uses SPAM algorithm introduced Howarth calculate instead. Our results suggest, stars cooler than about 5000 K, no methodology good enough explain effect; observe sharp deviation between measured predicted both order 1 , 0.2 cool stars. We recommend caution assuming perfectly known, particular these analyzing curves.