Exoplanets & Exomoons

How Rare Are TESS Free-Floating Planets?

By Keith Cowing
Status Report
May 6, 2024
Filed under , , , , ,
How Rare Are TESS Free-Floating Planets?
TESS Free-Floating Planet — NASA

Recently, Kunimoto et al. claimed that a short-lived signal in the Transiting Exoplanet Survey Satellite (TESS) Sector 61 database was caused by a microlensing event with a terrestrial-mass free-floating planet (FFP) lens.

In this study, we investigate TESS’s ability to detect microlensing FFPs by considering the detailed source information (e.g., distance and radius), the TESS photometric accuracy, and finite-source effects. Using the FFP mass function from microlensing surveys toward the Galactic bulge, we find that only 0.0018 microlensing events are expected to be detected in TESS Sector 61 for the entire planetary mass range.

The reported signal is unlikely to be a real microlensing event, which is consistent with the evidence from the long-term OGLE data that the signal was likely due to a stellar flare. By extrapolating our result to fainter stars until T=16 mag and adopting a possible optimized search algorithm, we find that only ∼1 FFP events can be detected in the entire TESS mission within the first 7 years.

Significant improvments of our understanding of FFPs still requires future satellite missions, such as Roman and Earth 2.0, which can detect thousands of FFPs.

Hongjing Yang, Weicheng Zang, Tianjun Gan, Renkun Kuang, Andrew Gould, Shude Mao

Comments: 7 pages, 4 figures. Submitted
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2405.02279 [astro-ph.EP] (or arXiv:2405.02279v1 [astro-ph.EP] for this version)
Submission history
From: Hongjing Yang
[v1] Fri, 3 May 2024 17:53:37 UTC (211 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻