Habitable Zones in Binary Star Systems Revisited

Habitable Zones with Stable Orbits for Planets around Binary Systems

Authors:

Jaime et al

Abstract:

A general formulation to compute habitable zones for binary stars is presented. We extend the simple formulation of the known concept: {\it circumstellar habitable zone} for single stars, to the case of eccentric stellar binary systems, where two sources of luminosity at different orbital phases contribute to the irradiance of their planetary circumstellar and circumbinary regions. Our approach considers binaries with eccentric orbits and guarantees that orbits in the computed habitable zone remain within it at all orbital phases. We apply this formulation to calculate habitable zones for binary stars of the solar neighborhood with known orbital parameters. Regions of stable, non-intersecting orbits, supported by invariant loops have been determined using the results of Pichardo, et al. 2005 and 2008, together with their habitable zones, are calculated for 51 cases, including some with discovered planets.

Formulae and interpolating tables are provided, so the reader can compute the boundaries of the habitable zones for an arbitrary binary system, using the stellar flux limits they prefer. Together with the formulae provided for stable zones, these allow the computation of both regions of stability and habitability around any binary stellar system. We found just that 50% of the cases we take can satisfy both restrictions, this is a very important constriction to binary systems, nevertheless our conclusion shows this kind of systems must be considered as strong candidates in the search for habitable planets and allow us to point some binaries as viable candidates.