Exoplanets & Exomoons

LHS 475 b: A Venus-sized Planet Orbiting a Nearby M Dwarf

By Keith Cowing
Status Report
April 17, 2023
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LHS 475 b: A Venus-sized Planet Orbiting a Nearby M Dwarf
Phase-folded photometry of LHS 475 highlighting the 3-hour window surrounding the planetary transits. Solid lines depict a best-fit model using the maximum a posteriori (MAP) estimates of the orbital period P and planet radius R. We produce separate subplots for TESS data (top panel), MEarth data (middle panel), and the combined TESS & MEarth data set (bottom panel). — astro-ph.EP

Based on photometric observations by TESS, we present the discovery of a Venus-sized planet transiting LHS 475, an M3 dwarf located 12.5 pc from the Sun.

The mass of the star is 0.274±0.015 MSun. The planet, originally reported as TOI 910.01, has an orbital period of 2.0291025±0.0000020 days and an estimated radius of 0.955±0.053 REarth. We confirm the validity and source of the transit signal with MEarth ground-based follow-up photometry of five individual transits. We present radial velocity data from CHIRON that rule out massive companions.

In accordance with the observed mass-radius distribution of exoplanets as well as planet formation theory, we expect this Venus-sized companion to be terrestrial, with an estimated RV semi-amplitude close to 1.0 m/s. LHS 475 b is likely too hot to be habitable but is a suitable candidate for emission and transmission spectroscopy.

Kristo Ment, David Charbonneau, Jonathan Irwin, Jennifer G. Winters, Emily Pass, Avi Shporer, Zahra Essack, Veselin B. Kostov, Michelle Kunimoto, Alan Levine, Sara Seager, Roland Vanderspek, Joshua N. Winn

Comments: 17 pages, 5 figures, submitted to AJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2304.01920 [astro-ph.EP] (or arXiv:2304.01920v1 [astro-ph.EP] for this version)
Submission history
From: Kristo Ment
[v1] Tue, 4 Apr 2023 16:15:35 UTC (1,416 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) 🖖🏻