Halo Photometry and Asteroseismology for 98 of the Brightest Stars Observed by TESS

Abstract

The Transiting Exoplanet Survey Satellite (TESS) mission has facilitated studies of asteroseismology, eclipsing binaries, and transits in many stars. However, the brightest stars saturate TESS, yet they are the most amenable to photon-hungry high-resolution studies and have long observational histories. In this work, we adapted the halo photometry used in $K$2 to extract light curves from the unsaturated halo pixels of the star's point spread function. We used this method to extract light curves for 98 of the brightest stars observed by TESS in Sectors 1-93. These bright stars include 15 red giants, five $δ$ Scuti variables, eight stochastic low-frequency variables, eight eclipsing binaries, and 46 other variables. We measured $ν_{\rm max}$ for 13 red giants using pyMON and $Δν$ for one of them, $β$ Gem (Pollux). For five of them, this represents the first time that oscillations were detected. We derived their stellar masses using the measured $ν_{\rm max}$ and previous interferometric and radiometric angular diameters. We also discovered $δ$ Scuti and $γ$ Doradus variability in $α$ Cep, possible asteroseismic binary signatures in $ε$ Car, and a new eclipsing binary, $γ$ And. Furthermore, we identified 18 stars in our sample that will be observed by the future PLAnetary Transits and Oscillations of stars (PLATO) mission, and 69 stars that have Stellar Observations Network Group (SONG) observations, including some simultaneous with TESS. The light curves are publicly available on the Mikulski Archive for Space Telescopes.