Pervasive Orbital Eccentricities Dictate the Habitability of Extrasolar Earths

Abstract

The long-term habitability of Earth-like planets requires low orbital eccentricities. A secular perturbation from a distant stellar companion is a very important mechanism in exciting planetary eccentricities, as many of the extrasolar planetary systems are associated with stellar companions. Although the orbital evolution of an Earth-like planet in a stellar binary is well understood, the effect of a binary perturbation to a more realistic system containing additional gas giant planets has been very little studied. Here we provide analytic criteria confirmed by a large ensemble of numerical integrations that identify the initial orbital parameters leading to eccentric orbits. We show that an extra-solar earth is likely to experience a broad range of orbital evolution dictated by the location of a gas-giant planet, necessitating more focused studies on the effect of eccentricity on the potential for life.

20 pages, 11 figures, to appear in Astrobiology

References in corpus (4)

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• Planetary Systems in Binaries. I. Dynamical Classification
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Cited by in corpus (5)

• The Habitable Zone and Extreme Planetary Orbits
• A Common Proper Motion Stellar Companion to HAT-P-7
• Light and Life: Exotic Photosynthesis in Binary Star Systems
• The most common habitable planets - atmospheric characterization of the subgroup of fast rotators
• Setting the Stage for Habitable Planets