Exoplanetology: Exoplanets & Exomoons

Planetary Edge Trends (PET). I. The Inner Edge-Stellar Mass Correlation

By Keith Cowing

Status Report

astro-ph.EP

January 12, 2025

Filed under astro-ph.EP, DR25, exoplanet, Gaia mission, hot jupiter, Interstellar, Kepler Data Release 25, LAMOST, Planetary Edge Trends, Stellar Cartography, sub-Neptune, super-Earth

Planetary Edge Trends (PET). I. The Inner Edge-Stellar Mass Correlation — A schematic comparison of the conclusions of this work and Mendigutía et al. (2024), revealing that the inner edges of different planetary systems correspond to different mechanisms. The results obtained in this work for small planets align more closely with the dust sublimation model, whereas their results obtained for giant planets are more consistent with migration up to the gas-truncation radius. — astro-ph.EP

The position of the innermost planet (i.e., the inner edge) in a planetary system provides important information about the relationship of the entire system to its host star properties, offering potentially valuable insights into planetary formation and evolution processes.

In this work, based on the Kepler Data Release 25 (DR25) catalog combined with LAMOST and Gaia data, we investigate the correlation between stellar mass and the inner edge position across different populations of small planets in multi-planetary systems, such as super-Earths and sub-Neptunes.
By correcting for the influence of stellar metallicity and analyzing the impact of observational selection effects, we confirm the trend that as stellar mass increases, the position of the inner edge shifts outward. Our results reveal a stronger correlation between the inner edge and stellar mass with a power-law index of 0.6-1.1, which is larger compared to previous studies.

The stronger correlation in our findings is primarily attributed to two factors: first, the metallicity correction applied in this work enhances the correlation; second, the previous use of occurrence rates to trace the inner edge weakens the observed correlation. Through comparison between observed statistical results and current theoretical models, we find that the pre-main-sequence (PMS) dust sublimation radius of the protoplanetary disk best matches the observed inner edge stellar mass.

Therefore, we conclude that the inner dust disk likely limits the innermost orbits of small planets, contrasting with the inner edges of hot Jupiters, which are associated with the magnetospheres of gas disks, as suggested by previous studies.

This highlights that the inner edges of different planetary populations are likely regulated by distinct mechanisms.

Meng-Fei Sun, Ji-Wei Xie, Ji-Lin Zhou, Beibei Liu, Nikolaos Nikolaou, Sarah C. Millholland

Comments: Submitted to A&A, 16 pages, 10 figures, 2 tables
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2501.02215 [astro-ph.EP] (or arXiv:2501.02215v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2501.02215
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Submission history
From: Meng-Fei Sun
[v1] Sat, 4 Jan 2025 07:13:02 UTC (1,658 KB)
https://arxiv.org/abs/2501.02215
Astrobiology,

Keith Cowing

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) 🖖🏻

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