An Analytic Method to determine Habitable Zones for S-Type Planetary Orbits in Binary Star Systems

TL;DR

This paper develops an analytical method to determine habitable zones for planets orbiting one star in binary systems, considering stellar perturbations and comparing with numerical simulations.

Contribution

It introduces a new analytical approach to assess habitable zones in binary systems, accounting for gravitational and radiative effects of the secondary star.

Findings

Habitability strongly depends on binary eccentricity.

Habitable zones can extend towards the secondary star in close binaries.

Analytical estimates align well with numerical simulations.

Abstract

With more and more extrasolar planets discovered in and around binary star systems, questions concerning the determination of the classical Habitable Zone arise. Do the radiative and gravitational perturbations of the second star influence the extent of the Habitable Zone significantly, or is it sufficient to consider the host-star only? In this article we investigate the implications of stellar companions with different spectral types on the insolation a terrestrial planet receives orbiting a Sun-like primary. We present time independent analytical estimates and compare these to insolation statistics gained via high precision numerical orbit calculations. Results suggest a strong dependence of permanent habitability on the binary's eccentricity, as well as a possible extension of Habitable Zones towards the secondary in close binary systems.