We use three-dimensional simulations to study the atmospheric circulation on
the first Earth-sized exoplanet discovered in the habitable zone of an M star.
We treat Gliese 581g as a scaled-up version of Earth by considering increased
values for the exoplanetary radius and surface gravity, while retaining
terrestrial values for parameters which are unconstrained by current
observations. We examine the long-term, global temperature and wind maps near
the surface of the exoplanet --- the climate. The specific locations for
habitability on Gliese 581g depend on whether the exoplanet is tidally-locked
and how fast radiative cooling occurs on a global scale. Independent of whether
the existence of Gliese 581g is confirmed, our study highlights the use of
general circulation models to quantify the atmospheric circulation on
potentially habitable, Earth-sized exoplanets, which will be the prime targets
of exoplanet discovery and characterization campaigns in the next decade.Comment: Accepted by MNRAS. 15 pages, 13 figures. Sample movies of simulations
are available at http://www.phys.ethz.ch/~kheng/fms
