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Title: Very wide binary stars as the primary source of stellar collisions in the galaxy

We present numerical simulations modeling the orbital evolution of very wide binaries, pairs of stars separated by over ∼10{sup 3} AU. Due to perturbations from other passing stars and the Milky Way's tide, the orbits of very wide binary stars occasionally become extremely eccentric, which forces close encounters between the companion stars. We show that this process causes a stellar collision between very wide binary companion stars once every 1000-7500 yr on average in the Milky Way. One of the main uncertainties in this collision rate is the amount of energy dissipated by dynamic tides during close (but not collisional) periastron passages. This dissipation presents a dynamical barrier to stellar collisions and can instead transform very wide binaries into close or contact binaries. However, for any plausible tidal dissipation model, very wide binary stars are an unrealized, and potentially the dominant, source of stellar collisions in our Galaxy. Such collisions should occur throughout the thin disk of the Milky Way. Stellar collisions within very wide binaries should yield a small population of single, Li-depleted, rapidly rotating massive stars.
Authors:
 [1] ;  [2]
  1. Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2131 Tech Drive, Evanston, IL 60208 (United States)
  2. Université de Bordeaux, LAB, UMR 5804, BP F-33270 Floirac (France)
Publication Date:
OSTI Identifier:
22351445
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 782; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; COLLISIONS; COMPUTERIZED SIMULATION; DIFFUSION BARRIERS; DISTURBANCES; EVOLUTION; MILKY WAY; ORBITS; PERTURBATION THEORY