Exosphere Modeling of Proxima b: A Case Study of Photochemical Escape with a Venus-like Atmosphere
arXiv:2109.06963 · doi:10.3847/1538-4357/ac26bb
Abstract
Exoplanets orbiting M-dwarfs within habitable zones are exposed to stellar environments more extreme than that terrestrial planets experience in our Solar System, which can significantly impact the atmospheres of the exoplanets and affect their habitability and sustainability. This study provides the first prediction of hot oxygen corona structure and the associated photochemical loss from a 1 bar CO2-dominated atmosphere of a Venus-like rocky exoplanet, where dissociative recombination of O2+ ions is assumed to be the major source reaction for the escape of neutral O atoms and formation of the hot O corona (or exospheres) as on Mars and Venus. We employ a 3D Monte Carlo code to simulate the exosphere of Proxima Centauri b (PCb) based on the ionosphere simulated by a 3D magnetohydrodynamic model. Our simulation results show that variability of the stellar wind dynamic pressure over one orbital period of PCb does not affect the overall spatial structure of the hot O corona but contributes to the change in the global hot O escape rate that varies by an order of magnitude. The escape increases dramatically when the planet possesses its intrinsic magnetic fields as the ionosphere becomes more extended with the presence of a global magnetic field. The extended hot O corona may lead to a more extended H exosphere through collisions between thermal H and hot O, which exemplifies the importance of considering nonthermal populations in exospheres to interpret future observations.
arXiv commentAccepted for publication in The Astrophysical Journal
References in corpus (25)
- A terrestrial planet candidate in a temperate orbit around Proxima Centauri
- The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample
- Theory of Low-Mass Stars and Substellar Objects
- Planetary evaporation by UV & X-ray radiation: basic hydrodynamics
- How Thermal Evolution and Mass Loss Sculpt Populations of Super-Earths and Sub-Neptunes: Application to the Kepler-11 System and Beyond
- Impact of Space Weather on Climate and Habitability of Terrestrial Type Exoplanets
- The habitability of Proxima Centauri b. I. Irradiation, rotation and volatile inventory from formation to the present
- Atmospheric escape from the TRAPPIST-1 planets and implications for habitability
- Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics
- Born Dry in the Photo-Evaporation Desert: Kepler's Ultra-Short-Period Planets Formed Water-Poor
- Is Proxima Centauri b habitable? -- A study of atmospheric loss
- The Solar Neighborhood XXXV: Distances to 1404 M Dwarf Systems Within 25 pc in the Southern Sky
- The Habitability of Proxima Centauri b: II: Environmental States and Observational Discriminants
- The Space Weather of Proxima Centauri b
- Exoplanet secondary atmosphere loss and revival
- XUV exposed non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets. Part I: Atmospheric expansion and thermal escape
- MOST Observations of our Nearest Neighbor: Flares on Proxima Centauri
- Modeling Martian Atmospheric Losses over Time: Implications for Exoplanetary Climate Evolution and Habitability
- Stellar wind interaction and pick-up ion escape of the Kepler-11 "super-Earths"
- The Interaction of Venus-like, M-dwarf Planets with the Stellar Wind of Their Host Star
- XUV exposed, non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets II: Hydrogen coronae and ion escape
- The dehydration of water worlds via atmospheric losses
- Atmospheric Escape From TOI-700 d: Venus versus Earth Analogs
- Role of planetary obliquity in regulating atmospheric escape: G-dwarf vs. M-dwarf Earth-like exoplanets
- Solar wind interaction with the Martian upper atmosphere: Roles of the cold thermosphere and hot oxygen corona