THERMAL ESCAPE FROM SUPER EARTH ATMOSPHERES IN THE HABITABLE ZONES OF M STARS Citation Tian, Feng. “THERMAL ESCAPE FROM SUPER EARTH ATMOSPHERES IN THE HABITABLE ZONES

نویسنده

  • Feng Tian
چکیده

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 CO2 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 CO2dominant 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.

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تاریخ انتشار 2009