Exoplanets & Exomoons

Searching For Free-Floating Planets with TESS: I. Discovery of a First Terrestrial-Mass Candidate

By Keith Cowing
Status Report
April 19, 2024
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Searching For Free-Floating Planets with TESS: I. Discovery of a First Terrestrial-Mass Candidate
This artist’s impression shows the free-floating planet CFBDSIR J214947.2-040308.9. — ESO

Though free-floating planets (FFPs) that have been ejected from their natal star systems may outpopulate their bound counterparts in the terrestrial-mass range, they remain one of the least explored exoplanet demographics.

Due to their negligible electromagnetic emission at all wavelengths, the only observational technique able to detect these worlds is gravitational microlensing. Microlensing by terrestrial-mass FFPs induces rare, short-duration magnifications of background stars, requiring high-cadence, wide-field surveys to detect these events.

The Transiting Exoplanet Survey Satellite (TESS), though designed to detect close-bound exoplanets via the transit technique, boasts a cadence as short as 200 seconds and has monitored hundreds of millions of stars, making it well-suited to search for short-duration microlensing events as well.

We have used existing data products from the TESS Quick-Look Pipeline (QLP) to perform a preliminary search for FFP microlensing candidates in 1.3 million light curves from TESS Sector 61. We find one compelling candidate associated with TIC-107150013, a source star at ds=3.194 kpc. The event has a duration tE=0.074+0.002−0.002 days and shows prominent finite-source features (ρ=4.55+0.08−0.07), making it consistent with an FFP in the terrestrial-mass range.

This exciting result indicates that our ongoing search through all TESS sectors has the opportunity to shed new light on this enigmatic population of worlds.

Michelle Kunimoto, William DeRocco, Nolan Smyth, Steve Bryson

Comments: 10 pages, 7 figures, submitted to MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2404.11666 [astro-ph.EP] (or arXiv:2404.11666v1 [astro-ph.EP] for this version)
Submission history
From: Michelle Kunimoto
[v1] Wed, 17 Apr 2024 18:04:11 UTC (2,758 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) 🖖🏻