Searching for Free-Floating Planets with TESS and Challenges for Future Microlensing Surveys
Nolan Smyth
Université de Montréal

Free-floating planets (FFPs) may be the most abundant type of terrestrial-mass exoplanets, yet they are much more challenging to detect than their bound counterparts. The short-duration magnification of background stars by FFP-induced gravitational microlensing, our best tool for studying this elusive population, requires high-cadence, wide-field surveys to detect. The Transiting Exoplanet Survey Satellite (TESS), though designed to detect close-bound exoplanets via transits, has a cadence as short as 200 seconds and has monitored hundreds of millions of stars, providing a unique dataset for short-duration transient events. A preliminary search of TESS light curves found one short-duration event of interest because its morphology matches expectations for a terrestrial-mass FFP. But the low expected microlensing rate, short observational baseline, and source magnetic activity challenge this interpretation. We also explore the false positive scenario of a stellar flare, but this too is unlikely. The event may constitute a first example of the new classes of pernicious false positive that future space-based microlensing efforts will encounter. By characterizing such events, our search across all TESS sectors will support upcoming studies of rogue worlds with dedicated space-based microlensing surveys.

Date:	Jeudi, le 27 février 2025
Heure:	11:00
Lieu:	Pour tous
	A-4502.1