THERMAL ESCAPE FROM SUPER EARTH ATMOSPHERES IN THE HABITABLE ZONES OF M STARS

Journal Article · Sun Sep 20 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/703/1/905· OSTI ID:21371956

Feng, Tian ^[1]

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1. Now at Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309, USA. (United States)

A fundamental question for exoplanet habitability is the long-term stability of the planet's atmosphere. We numerically solve a one-dimensional multi-component hydrodynamic thermosphere/ionosphere model to examine the thermal and chemical responses of the primary CO{sub 2} atmospheres of heavy super Earths (6-10 Earth masses) in the habitable zones of typical low-mass M stars to the enhanced soft X-ray and ultraviolet (XUV) fluxes associated with the prolonged high-activity levels of M stars. The results show that such atmospheres are stable against thermal escape, even for M stars XUV enhancements as large as 1000 compared to the present Earth. It is possible that the CO{sub 2}-dominant atmospheres of super Earths in the habitable zones of M stars could potentially contain modest amount of free oxygen as a result of more efficient atmosphere escape of carbon than oxygen instead of photosynthesis.

• OSTI ID: 21371956
• Journal Information: Astrophysical Journal, Vol. 703, Issue 1; Other Information: DOI: 10.1088/0004-637X/703/1/905; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACTIVITY LEVELS
CARBON
CARBON DIOXIDE
EXTREME ULTRAVIOLET RADIATION
IONOSPHERE
MASS
PHOTOSYNTHESIS
PLANETS
SATELLITES
SOFT X RADIATION
STARS
THERMOSPHERE
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
ELEMENTS
IONIZING RADIATIONS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATIONS
SYNTHESIS
ULTRAVIOLET RADIATION
X RADIATION