Is Proxima Centauri b habitable? -- A study of atmospheric loss

Abstract

We address the important question of whether the newly discovered exoplanet, Proxima Centauri b (PCb), is capable of retaining an atmosphere over long periods of time. This is done by adapting a sophisticated multi-species MHD model originally developed for Venus and Mars, and computing the ion escape losses from PCb. The results suggest that the ion escape rates are about two orders of magnitude higher than the terrestrial planets of our Solar system if PCb is unmagnetized. In contrast, if the planet does have an intrinsic dipole magnetic field, the rates are lowered for certain values of the stellar wind dynamic pressure, but they are still higher than the observed values for our Solar system's terrestrial planets. These results must be interpreted with due caution, since most of the relevant parameters for PCb remain partly or wholly unknown.

7 pages, 2 figures, accepted for publication in ApJL

References in corpus (11)

• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• A Re-appraisal of the Habitability of Planets Around M Dwarf Stars
• The habitability of Proxima Centauri b II. Possible climates and Observability
• The habitability of Proxima Centauri b. I. Irradiation, rotation and volatile inventory from formation to the present
• The Solar Neighborhood XXXV: Distances to 1404 M Dwarf Systems Within 25 pc in the Southern Sky
• The Space Weather of Proxima Centauri b
• Magnetospheric Structure and Atmospheric Joule Heating of Habitable Planets Orbiting M-dwarf Stars
• Occurrence and core-envelope structure of 1--4x Earth-size planets around Sun-like stars
• Prospects for Characterizing the Atmosphere of Proxima Centauri b
• The Interaction of Venus-like, M-dwarf Planets with the Stellar Wind of Their Host Star
• Tutorial models of the climate and habitability of Proxima Centauri b: a thin atmosphere is sufficient to distribute heat given low stellar flux

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• Reduced Diversity of Life Around Proxima Centauri and TRAPPIST-1
• A Helicity-Based Method to Infer the CME Magnetic Field Magnitude in Sun and Geospace: Generalization and Extension to Sun-Like and M-Dwarf Stars and Implications for Exoplanet Habitability
• Photogravimagnetic assists of light sails: a mixed blessing for Breakthrough Starshot?