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

TL;DR

This study analyzes photometric data of star BD-06 1339 and suggests that its previously reported exoplanet signal is likely a false positive caused by stellar activity, highlighting challenges in exoplanet detection.

Contribution

It provides evidence that stellar activity can mimic planetary signals in radial velocity data, emphasizing the importance of combined photometric and spectroscopic analysis.

Findings

Photometric variability matches the radial velocity period

Stellar activity likely caused the false positive signal

Highlights need for additional data to confirm exoplanet presence

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.