THE ROTATION RATES OF MASSIVE STARS: THE ROLE OF BINARY INTERACTION THROUGH TIDES, MASS TRANSFER, AND MERGERS

• Published in: The Astrophysical journal Vol. 764; no. 2; pp. 1 - 17
• Main Authors: de Mink, S E, Langer, N, Izzard, R G, Sana, H, DE KOTER, A
• Format: Journal Article
• Language: English
• Published: United States 20-02-2013
• Subjects: Acquisitions; ASTRONOMY; ASTROPHYSICS; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; COSMIC GAMMA BURSTS; Evolution; Explosions; GALAXIES; Gamma ray bursts; INTERSTELLAR MAGNETIC FIELDS; MAIN SEQUENCE STARS; MASS TRANSFER; Massive stars; RED SHIFT; ROTATION; STAR EVOLUTION; Stars; STELLAR WINDS; Tides; UNIVERSE
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/764/2/166

Rotation is thought to be a major factor in the evolution of massive stars-especially at low metallicity-with consequences for their chemical yields, ionizing flux, and final fate. We investigate how this affects the distribution of rotation rates, through stellar winds, expansion, tides, mass transfer, and mergers. For this purpose, we simulate a massive binary-star population typical for our Galaxy assuming continuous star formation. We find that, because of binary interaction, 20 super(+5) sub(-10)% of all massive main-sequence stars have projected rotational velocities in excess of 200 km s super(-1). The fraction of rapid rotators we derive is similar to that observed. If indeed mass transfer and mergers are the main cause for rapid rotation in massive stars, little room remains for rapidly rotating stars that are born single. Furthermore, our results allow for the possibility that all early-type Be stars result from binary interactions and suggest that evidence for rotation in explosions, such as long gamma-ray bursts, points to a binary origin.