Lifetime Against Sublimation and an Initial Mass Estimate for the Exoplanet α Centauri Bb
American Journal of Astronomy and Astrophysics
Volume 3, Issue 4, July 2015, Pages: 70-76
Received: Aug. 22, 2015; Accepted: Sep. 6, 2015; Published: Sep. 18, 2015
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Authors
Martin Beech, Campion College, the University of Regina, Regina, SK., Canada; Department of Physics, the University of Regina, Regina, SK., Canada
Lowell Peltier, Department of Physics, the University of Regina, Regina, SK., Canada
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Abstract
A two-component, core-mantle, model is developed to estimate the lifetime against destruction via sublimation of close-orbit, terrestrial-mass exoplanets. We specifically focus on the nearest terrestrial exoplanet, α Centauri Bb, since the parent star α Cen B has a reasonably well determined age of 6 ± 1 Gyr. This latter knowledge specifically enables an estimate to be made of the amount of mantle material lost by α Cen Bb since the system formed. Our planet model allows for an iron-core and olivine mantle structure, and it also follows the luminosity evolution of α Cen B. Our results suggest that α Cen Bb had an initial mass of order 2 MEarth, and that of order 0.2 MEarth of mantle material has been lost through sublimation since the planet formed. We additionally consider the fate of any putative planets, moving on circular orbits, interior to α Cen Bb (which has an orbital radius of 0.04 au), and it is found that any Earth mass, or lesser objects, orbiting closer than 0.024 au to α Cen B have lifetimes against destruction by sublimation smaller than 5 billion years.
Keywords
Exoplanets, α Centauri AB Star System, α Centauri Bb, Sublimation Lifetime
To cite this article
Martin Beech, Lowell Peltier, Lifetime Against Sublimation and an Initial Mass Estimate for the Exoplanet α Centauri Bb, American Journal of Astronomy and Astrophysics. Vol. 3, No. 4, 2015, pp. 70-76. doi: 10.11648/j.ajaa.20150304.11
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