Calculating the Habitable Zone of Binary Star Systems

We have developed a simple approach to assess the influence of the secondary star on the limits of the habitable zone and habitability of terrestrial planets around the primary of a binary system. We consider different stellar spectral types for the primary and secondary, and by combining dynamical simulations with the influence of the additional flux, have derived the binary’s habitable zone as a function of its semimajor axis, eccentricity, and stellar energy distribution for a CO2/H2O/N2 atmosphere. We find that terrestrial planets can be habitable and stable for a variety of binary eccentricities. Our results indicate that the effect of the secondary star on the locations of the primary’s habitable zone is generally small. However, this star can influence the extent of the habitable zone significantly when the binary’s separation is small and its orbit is eccentric.