1202.1265 (Duncan Forgan)
Duncan Forgan
The Alpha Centauri AB system is an attractive one for radial velocity
observations to detect potential exoplanets. The high metallicity of both Alpha
Centauri A and B suggest that they could have possessed circumstellar discs
capable of forming planets. As the closest star system to the Sun, with well
over a century of accurate astrometric measurements (and Alpha Centauri B
exhibiting low chromospheric activity) high precision surveys of Alpha Centauri
B's potential exoplanetary system are possible with relatively cheap
instrumentation. Authors studying habitability in this system typically adopt
habitable zones (HZs) based on global radiative balance models that neglect the
radiative perturbations of Alpha Centauri A.
We investigate the habitability of planets around Alpha Centauri B using 1D
latitudinal energy balance models (LEBMs), which fully incorporate the presence
of Alpha Centauri A as a means of astronomically forcing terrestrial planet
climates. We find that the extent of the HZ is relatively unchanged by the
presence of Alpha Centauri A, but there are variations in fractional
habitability for planets orbiting at the boundaries of the zone due to Alpha
Centauri A, even in the case of zero eccentricity. Temperature oscillations of
a few K can be observed at all planetary orbits, the strength of which varies
with the planet's ocean fraction and obliquity.
View original:
http://arxiv.org/abs/1202.1265
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