2019/07/31 by Chuanfei Dong, Zhenguang Huang, Manasvi Lingam · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Atmosphere (unit) #Atmospheric escape #Atmospheric models #Circumstellar habitable zone #Exoplanet #Planet #Planetary habitability #Solar System #Solar and Space Plasma Dynamics #Stellar, planetary, and galactic studies #Tidal locking #astro-ph.EP #astro-ph.SR #physics.space-ph
paper · pdf · doi:10.3847/2041-8213/ab372c
published as ApJ Letters, 882, L16, 2019 · ApJ Letters, in press, 10 pages, 3 figures and 2 tables
openalex created_date 2019/07/23 · arxiv created 2019/07/31 · openalex publication_date 2019/09/05 · arxiv updated 2019/12/10 · openalex updated_date 2026/08/06
Abstract We present a three-species (H + , O + and e − ) multi-fluid magnetohydrodynamic model, endowed with the requisite upper-atmospheric chemistry, that is capable of accurately quantifying the magnitude of oxygen ion losses from “Earth-like” exoplanets in habitable zones, whose magnetic and rotational axes are roughly coincidental with one another. We apply this model to investigate the role of planetary obliquity in regulating atmospheric losses from a magnetic perspective. For Earth-like exoplanets orbiting solar-type stars, we demonstrate that the dependence of the total atmospheric ion loss rate on the planetary (magnetic) obliquity is relatively weak; the escape rates are found to vary between 2.19 × 10 26 s −1 to 2.37 × 10 26 s −1 . In contrast, the obliquity can influence the atmospheric escape rate (∼10 28 s −1 ) by more than a factor of 2 (or 200%) in the case of Earth-like exoplanets orbiting late-type M-dwarfs. Thus, our simulations indicate that planetary obliquity may play a weak-to-moderate role insofar as the retention of an atmosphere (necessary for surface habitability) is concerned.