TESS Discovery of an ultra-short-period planet around the nearby M dwarf LHS 3844

TL;DR

TESS discovered an ultra-short-period, Earth-sized exoplanet orbiting the nearby M dwarf LHS 3844, providing opportunities for atmospheric and mass measurements due to the star's brightness and the planet's short orbital period.

Contribution

First detection of an ultra-short-period planet around a nearby M dwarf using TESS data, highlighting its potential for atmospheric and mass characterization.

Findings

Planet radius of 1.32 Earth radii

Orbital period of 11 hours

Star's brightness suitable for follow-up studies

Abstract

Data from the newly-commissioned \textit{Transiting Exoplanet Survey Satellite} (TESS) has revealed a "hot Earth" around LHS 3844, an M dwarf located 15 pc away. The planet has a radius of $1.32\pm 0.02$ $R_\oplus$ and orbits the star every 11 hours. Although the existence of an atmosphere around such a strongly irradiated planet is questionable, the star is bright enough ($I=11.9$, $K=9.1$) for this possibility to be investigated with transit and occultation spectroscopy. The star's brightness and the planet's short period will also facilitate the measurement of the planet's mass through Doppler spectroscopy.