_version_ 1866912963076554752
author Brain, David A.
Cohen, Ofer
Cravens, Thomas E.
France, Kevin
Glocer, Alex
Hinton, Parker
Leblanc, Francois
Ma, Yingjuan
Nakayama, Akifumi
Sakai, Shotaro
Sakata, Ryoya
Seki, Kanako
Alvarado-Gómez, Julián D.
Berta-Thompson, Zachory
Cangi, Eryn M.
Chaffin, Michael
Chaufray, Jean-Yves
Frelikh, Renata
Futaana, Yoshifumi
Garcia-Sage, Katherine
Hanson, Lukas
Holmström, Mats
Jakosky, Bruce
Jarvinen, Riku
Kopparapu, Ravi
Marsh, Daniel R.
Merkel, Aimee
Moore, Thomas Earle
Notsu, Yuta
Osten, Rachel A.
Peterson, William K.
Peticolas, Laura
Ramstad, Robin
Stevenson, Kevin B.
Strangeway, Robert
Sun, Wenyi
Terada, Naoki
Vidotto, Aline A.
author_facet Brain, David A.
Cohen, Ofer
Cravens, Thomas E.
France, Kevin
Glocer, Alex
Hinton, Parker
Leblanc, Francois
Ma, Yingjuan
Nakayama, Akifumi
Sakai, Shotaro
Sakata, Ryoya
Seki, Kanako
Alvarado-Gómez, Julián D.
Berta-Thompson, Zachory
Cangi, Eryn M.
Chaffin, Michael
Chaufray, Jean-Yves
Frelikh, Renata
Futaana, Yoshifumi
Garcia-Sage, Katherine
Hanson, Lukas
Holmström, Mats
Jakosky, Bruce
Jarvinen, Riku
Kopparapu, Ravi
Marsh, Daniel R.
Merkel, Aimee
Moore, Thomas Earle
Notsu, Yuta
Osten, Rachel A.
Peterson, William K.
Peticolas, Laura
Ramstad, Robin
Stevenson, Kevin B.
Strangeway, Robert
Sun, Wenyi
Terada, Naoki
Vidotto, Aline A.
contents Atmospheric escape is an important process that influences the evolution of planetary atmospheres. A variety of physical mechanisms can contribute to escape from an atmosphere, including thermal escape, ion escape, photochemical escape, and sputtering. Here we estimate escape rates via each of these processes for a hypothetical Mars-like exoplanet orbiting Barnard's star (an old, inactive M dwarf star). We place the planet at an orbital distance that receives the same total stellar flux as it does in our solar system. We use the measured stellar extreme ultraviolet (EUV) spectrum and assumptions on the star's magnetic field to determine both the high-energy radiation and the stellar wind environment around the planet. This information is used to model the response of the planet's thermosphere, exosphere and magnetosphere using a variety of models that have been validated against solar system observations. We find overall escape rates that are dominated by thermal processes and elevated by 2-5 orders of magnitude relative to present-day Mars, suggesting that a Mars-like planet orbiting Barnard's star would not retain a significant atmosphere for more than 10's of millions of years. Recently reported planets around Barnard's star should also not have retained significant atmospheres. By extension, Mars-like planets orbiting any M dwarf near the 'Habitable Zone' should not retain atmospheres for extended periods of time.
format Preprint
id arxiv_https___arxiv_org_abs_2603_11561
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Atmospheric Escape Rates from Mars - If it Orbited an Old M-Dwarf Star
Brain, David A.
Cohen, Ofer
Cravens, Thomas E.
France, Kevin
Glocer, Alex
Hinton, Parker
Leblanc, Francois
Ma, Yingjuan
Nakayama, Akifumi
Sakai, Shotaro
Sakata, Ryoya
Seki, Kanako
Alvarado-Gómez, Julián D.
Berta-Thompson, Zachory
Cangi, Eryn M.
Chaffin, Michael
Chaufray, Jean-Yves
Frelikh, Renata
Futaana, Yoshifumi
Garcia-Sage, Katherine
Hanson, Lukas
Holmström, Mats
Jakosky, Bruce
Jarvinen, Riku
Kopparapu, Ravi
Marsh, Daniel R.
Merkel, Aimee
Moore, Thomas Earle
Notsu, Yuta
Osten, Rachel A.
Peterson, William K.
Peticolas, Laura
Ramstad, Robin
Stevenson, Kevin B.
Strangeway, Robert
Sun, Wenyi
Terada, Naoki
Vidotto, Aline A.
Earth and Planetary Astrophysics
Atmospheric escape is an important process that influences the evolution of planetary atmospheres. A variety of physical mechanisms can contribute to escape from an atmosphere, including thermal escape, ion escape, photochemical escape, and sputtering. Here we estimate escape rates via each of these processes for a hypothetical Mars-like exoplanet orbiting Barnard's star (an old, inactive M dwarf star). We place the planet at an orbital distance that receives the same total stellar flux as it does in our solar system. We use the measured stellar extreme ultraviolet (EUV) spectrum and assumptions on the star's magnetic field to determine both the high-energy radiation and the stellar wind environment around the planet. This information is used to model the response of the planet's thermosphere, exosphere and magnetosphere using a variety of models that have been validated against solar system observations. We find overall escape rates that are dominated by thermal processes and elevated by 2-5 orders of magnitude relative to present-day Mars, suggesting that a Mars-like planet orbiting Barnard's star would not retain a significant atmosphere for more than 10's of millions of years. Recently reported planets around Barnard's star should also not have retained significant atmospheres. By extension, Mars-like planets orbiting any M dwarf near the 'Habitable Zone' should not retain atmospheres for extended periods of time.
title Atmospheric Escape Rates from Mars - If it Orbited an Old M-Dwarf Star
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2603.11561