Exoplanets & Exomoons

Searching For Giant Exoplanets Around M-dwarf Stars (GEMS) I: Survey Motivation

By Keith Cowing
Status Report
February 9, 2024
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Searching For Giant Exoplanets Around M-dwarf Stars (GEMS) I: Survey Motivation
Green triangles show an estimate of the heavyelement content (MZ ) of GEMS from planetary interior models (Thorngren et al. 2016) compared to the Class II disk dust mass (Md) estimates as orange squares (Manara et al. 2022) and the median (and 1-σ) trend seen in the Lupus sample (Ansdell et al. 2016). The green arrows show the approximate expected disk dust masses required to form the green triangles assuming 10% formation efficiency (Liu et al. 2019b). The red line shows the range of dust masses for Class 0 and I disks from Tychoniec et al. (2020). Takeaway: The formation of GEMS necessitates disks with many 100s of M⊕ of heavy-elements. This could be achieved by anomalously massive Class II disks with underestimated dust masses, or Class 0/I disks. — astro-ph.EP

Recent discoveries of transiting giant exoplanets around M-dwarf stars (GEMS), aided by the all-sky coverage of TESS, are starting to stretch theories of planet formation through the core-accretion scenario. Recent upper limits on their occurrence suggest that they decrease with lower stellar masses, with fewer GEMS around lower-mass stars compared to solar-type.

In this paper, we discuss existing GEMS both through confirmed planets, as well as protoplanetary disk observations, and a combination of tests to reconcile these with theoretical predictions. We then introduce the Searching for GEMS survey, where we utilize multi-dimensional nonparameteric statistics to simulate hypothetical survey scenarios to predict the required sample size of transiting GEMS with mass measurements to robustly compare their bulk-density with canonical hot-Jupiters orbiting FGK stars.

Our Monte-Carlo simulations predict that a robust comparison requires about 40 transiting GEMS (compared to the existing sample of ∼ 15) with 5-σ mass measurements. Furthermore, we discuss the limitations of existing occurrence estimates for GEMS, and provide a brief description of our planned systematic search to improve the occurrence rate estimates for GEMS.

Shubham Kanodia, Caleb I. Cañas, Suvrath Mahadevan, Eric B. Ford, Ravit Helled, Dana E. Anderson, Alan Boss, William D. Cochran, Megan Delamer, Te Han, Jessica E. Libby-Roberts, Andrea S.J. Lin, Simon Müller, Paul Robertson, Guðmundur Stefánsson, Johanna Teske

Comments: 16 pages + references, including 7 figures. Accepted in AAS Journals
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2402.04946 [astro-ph.EP] (or arXiv:2402.04946v1 [astro-ph.EP] for this version)
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Submission history
From: Shubham Kanodia
[v1] Wed, 7 Feb 2024 15:30:17 UTC (600 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) 🖖🏻