Revisiting BD-06 1339b: A Likely False Positive Caused by Stellar Activity

Abstract

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 variability detected in the photometric data are consistent with the periodic signal. We conclude that the previously reported planetary signature is likely the result of a false positive signal resulting from stellar activity, and discuss the need for more data to confirm this conclusion.

9 pages, 3 figures, accepted to The Astronomical Journal

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