2023AJ....165..265M -
Astron. J., 165, 265 (2023/June-0)
The Occurrence Rate of Terrestrial Planets Orbiting Nearby Mid-to-late M Dwarfs from TESS Sectors 1-42.
MENT K. and CHARBONNEAU D.
Abstract (from CDS):
We present an analysis of a volume-complete sample of 363 mid-to-late M dwarfs within 15 pc of the Sun with masses between 0.1 and 0.3 M⊙ observed by TESS within sectors 1-42. The median stellar mass of the sample is 0.17 M⊙. We search the TESS light curves for transiting planets with orbital periods below 7 days and recover all six known planets within the sample, as well as a likely planet candidate orbiting LHS 475. Each of these planets is consistent with a terrestrial composition, with planet radii between 0.91 and 1.31 R⊕. We characterize the transit detection sensitivity for each star as a function of planet radius, insolation, and orbital period. We obtain a cumulative occurrence rate of ${0.61}_{-0.19}^{+0.24}$ terrestrial planets per star with radii above 0.5 R⊕ and orbital periods between 0.4 and 7 days. We find that for comparable insolations, planets larger than 1.5 R⊕ (sub-Neptunes) are significantly less abundant around mid-to-late M dwarfs compared to earlier-type stars, while the occurrence rate of terrestrial planets is comparable to that of more massive M dwarfs. We estimate that overall, terrestrials outnumber sub-Neptunes around mid-to-late M dwarfs by 14 to 1, in contrast to GK dwarfs, where they are roughly equinumerous. We place a 1σ upper limit of 0.07 planets larger than 1.5 R⊕ per star within the orbital period range of 0.5-7 days. We find evidence for a downturn in occurrence rates for planet radii below 0.9 R⊕, suggesting that Earth-sized and larger terrestrials may be more common around mid-to-late M dwarfs.
Abstract Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Transit photometry - Exoplanet systems - Exoplanets - Low mass stars - Transits
VizieR on-line data:
<Available at CDS (J/AJ/165/265): table1.dat>
Simbad objects:
332
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