Atmospheres of Hot Super-Earths
Abstract
Hot super-Earths likely possess minimal atmospheres established through vapor saturation equilibrium with the ground. We solve the hydrodynamics of these tenuous atmospheres at the surface of CoRot-7b, Kepler-10b, and 55 Cnc-e, including idealized treatments of magnetic drag and ohmic dissipation. We find that atmospheric pressures remain close to their local saturation values in all cases. Despite the emergence of strongly supersonic winds which carry sublimating mass away from the substellar point, the atmospheres do not extend much beyond the day-night terminators. Ground temperatures, which determine the planetary thermal (infrared) signature, are largely unaffected by exchanges with the atmosphere and thus follow the effective irradiation pattern. Atmospheric temperatures, however, which control cloud condensation and thus albedo properties, can deviate substantially from the irradiation pattern. Magnetic drag and ohmic dissipation can also strongly impact the atmospheric behavior, depending on atmospheric composition and the planetary magnetic field strength. We conclude that hot super-Earths could exhibit interesting signatures in reflection (and possibly in emission) which would trace a combination of their ground, atmospheric, and magnetic properties.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2011
- DOI:
- 10.1088/2041-8205/743/2/L36
- arXiv:
- arXiv:1109.0659
- Bibcode:
- 2011ApJ...743L..36C
- Keywords:
-
- hydrodynamics;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 14 pages, 4 figures, 1 table, accepted for publication in ApJL