title: 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 system is well understood, the effect of a binary perturbation on 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 extrasolar earth is likely to experience a broad range of orbital evolution dictated by the location of a gas-giant planet, which necessitates more focused studies on the effect of eccentricity on the potential for life.
authors.affiliation: Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kita
authors.forename: Frederic
authors.initials: F
authors.lastname: Rasio
authors.forename: Genya
authors.initials: G
authors.lastname: Takeda
mesh_terms: D055580:Astronomical Phenomena; D055907:Climatic Processes; D019419:Evolution, Planetary; D005118:Extraterrestrial Environment; D018561:Space Simulation / Q000379:methods; D055609:Stars, Celestial; D013995:Time; D014867:Water
chemical_list: D014867:Water