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Title: V1309 Sco—understanding a merger

One of the two outcomes of a common envelope (CE) event is a merger of the two stars. To date, the best known case of a binary merger is the V1309 Sco outburst, where the orbital period was known and observed to decay up to the outburst. Using the hydrodynamical code StarSmasher, we study in detail which characteristics of the progenitor binary affect the outburst and produce the best match with observations. We have developed a set of tools in order to quantify any CE event. We consider binaries consisting of a 1.52 M {sub ☉} giant and a 0.16 M {sub ☉} companion with P {sub orb} ∼ 1.4 days, varying the nature of the companion and its synchronization. We show that all considered progenitor binaries evolve toward the merger primarily because of Darwin instability. The merger is accompanied by mass ejection that proceeds in several separate mass outbursts and takes away a few percent of the donor mass. This very small mass, nonetheless, is important as it is not only sufficient to explain the observed light curve, but it also carries away up to one-third of both the initial total angular momentum and initial orbital energy. We findmore » that all synchronized systems experience L {sub 2} mass loss that operates during just a few days prior to the merger and produces ring-shaped ejecta. The formed star is always a strongly heated radiative star that differentially rotates. We conclude that the case of a synchronized binary with a main-sequence companion gives the best match with observations of V1309 Sco.« less
Authors:
;  [1] ;  [2]
  1. Department of Physics, University of Alberta, Edmonton, AB, T6G 2E7 (Canada)
  2. Department of Physics, Allegheny College, Meadville, PA 16335 (United States)
Publication Date:
OSTI Identifier:
22357010
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 786; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANGULAR MOMENTUM; BINARY STARS; DECAY; GALAXIES; HYDRODYNAMICS; INSTABILITY; MASS TRANSFER; ROTATION; STARS; STELLAR WINDS; SYNCHRONIZATION; VISIBLE RADIATION