Exoplanets & Exomoons

Assessing TESS's Yield of Rocky Planets Around Nearby M Dwarfs

By Keith Cowing
Press Release
December 15, 2021
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Assessing TESS's Yield of Rocky Planets Around Nearby M Dwarfs
Exoplanet circling an M class star

Terrestrial planets are easier to detect around M dwarfs than other types of stars, making them promising for next-generation atmospheric characterization studies.

The TESS mission has greatly increased the number of known M dwarf planets that we can use to perform population studies, allowing us to explore how the rocky planet occurrence rate varies with host radius, following in the footsteps of past work with Kepler data. In this paper, we use simulations to assess TESS’s yield of small (Rp<2R⊕) planet candidates around nearby (d<30 pc) M dwarfs.

We highlight the underappreciated fact that while TESS was indeed expected to find a large number of planets around M dwarfs overall, it was not expected to have a high planetary yield for the latest M dwarfs. Furthermore, we find that TESS has detected significantly fewer planets around stars with R⋆<0.3R⊙ than even was expected (11 observed vs. 23±5 expected). We find evidence that the photometric noise of stars in the TESS bandpass increases with decreasing radius for M dwarfs. However, this trend cannot explain the observed distribution of planets.

Our main conclusions are: (1) the planetary occurrence rate likely doesn’t increase, and may decrease for the latest M dwarfs; and (2) there are at least 17, and potentially three times that number, transiting planets around nearby late M dwarfs that will still not be detected by the end of TESS’s 4th year.

Madison Brady, Jacob Bean Comments: 11 pages, 4 figures, 1 table. Submitted to AAS journals, comments welcome
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2112.08337 [astro-ph.EP] (or arXiv:2112.08337v1 [astro-ph.EP] for this version)
Submission history
From: Madison Brady
[v1] Wed, 15 Dec 2021 18:35:06 UTC (1,973 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) 🖖🏻