False Positive Exoplanet Induced by Stellar Variability

As long as astronomers have searched for exoplanets, the intrinsic variability of host stars has interfered with the ability to reliably detect and confirm exoplanets. One particular source of false positives is the presence of stellar magnetic or chromospheric activity that can mimic the radial-velocity reflex motion of a planet. Here we present the results of a photometric data analysis for the known planet hosting star, BD-06 1339, observed by the Transiting Exoplanet Survey Satellite (TESS) during Sector 6 at 2 minute cadence. We discuss evidence that suggests the observed 3.9 day periodic radial velocity signature may be caused by stellar activity rather than a planetary companion, since the measured photometric variability is consistent with the periodic radial velocity signal. This false positive exoplanet is a product of our broader analysis on the photometric variability of all known exoplanet host stars observed by TESS, from which we aim to further understand star-planet interactions.