Searching for free-floating planets with TESS: I. Discovery of the first terrestrial-mass candidate

Although free-floating planets (FFPs) are ejected from their natal star systems and exceed their bounds in the terrestrial-mass range, they remain one of the least explored exoplanet populations.

Because of their very low electromagnetic emission at all wavelengths, the only observational technique that can detect these worlds is gravitational microlensing. Microlensing of terrestrial-mass FFPs induces rare, short-lived magnifications of background stars, requiring high-resolution, wide-field surveys to detect these events.

The Transiting Exoplanet Survey Satellite (TESS), although designed to detect close-in exoplanets using the transit technique, has a short period of up to 200 seconds and has tracked hundreds of millions of stars, making it ideal for short-term searches. Microlensing phenomena as well.

We used existing data products from the TESS Quick-Look Pipeline (QLP) to perform an initial search for FFP microlensing candidates in 1.3 million light arcs from TESS Sector 61. ds=3.194 kpc. The duration of the event is tE=0.074+0.002−0.002 days and shows prominent finite source features (ρ=4.55+0.08−0.07), consistent with FFP in the terrestrial-mass range.

This exciting result indicates that our ongoing search across all TESS fields has the potential to shed new light on this enigmatic population of worlds.

Michael Kunimoto, William Drocco, Nolan Smith, Steve Bryson

Comments: 10 pages, 7 figures, submitted to MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of the Galaxies (astro-ph.GA); Astrophysical Instruments and Methods (astro-ph.IM)
Citation: arXiv:2404.11666 [astro-ph.EP] (or arXiv:2404.11666v1 [astro-ph.EP] for this version)
Submission history
Posted by: Michael Kunimoto
[v1] Wed, 17 Apr 2024 18:04:11 UTC (2,758 KB)
https://arxiv.org/abs/2404.11666
Astronomy