Stellar Variability Catalog of Stars Observed During the TESS Primary Mission

Characterizing exoplanets first requires precise measurements of their host star’s properties. In addition to revealing possible companions, the shape and periodic nature of a star’s light curve can uncover important information about its intrinsic properties. Stellar pulsations and rotational modulations, for example, are inherently linked to a star’s evolutionary stage and thus can be used to infer stellar ages. Furthermore, stellar variability may induce false planetary signals in radial velocity measurements or hide transit events of small exoplanets. The TESS spacecraft obtained high-precision space-based time-series photometry of nearly the entire sky during its primary mission, allowing for a large-scale study of stellar variability that is not sensitive to the diurnal limitation of ground-based surveys. We have developed a stellar variability catalog that includes ~40,000 stars that exhibit significant photometric variability on timescales of 0.01-13 days, which could be attributed to rotational modulations, stellar pulsations, or binarity. We will discuss the characteristics of the stars in our stellar variability catalog, which we anticipate will be released to the community prior to the Exoplanets IV meeting. Our stellar variability catalog will serve as a valuable resource to the stellar astrophysics and exoplanet communities, in that it will aid in 1) studying the characteristics of periodic variable stars; 2) understanding interactions between host star variability and planetary atmospheres; and 3) identifying exoplanets that are actually false positives caused by stellar variability. Overall, this work also encompasses understanding “worlds and Suns in context,” which has been identified as a high-priority area of research by the Astronomy 2020 Decadal Survey.