The Early Angular Momentum History of Low-Mass Stars: Evidence for a Regulation Mechanism
Author(s) -
L. M. Rebull,
Sidney C. Wolff,
S. E. Strom,
Russell B. Makidon
Publication year - 2002
Publication title -
the astronomical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.61
H-Index - 271
eISSN - 1538-3881
pISSN - 0004-6256
DOI - 10.1086/340806
Subject(s) - orion nebula , physics , stars , angular momentum , astrophysics , astronomy , cluster (spacecraft) , classical mechanics , computer science , programming language
We examine the early angular momentum history of stars in young clusters via197 photometric periods in fields flanking the Orion Nebula Cluster (ONC), 81photometric periods in NGC 2264, and 202 measurements of v sin i in the ONCitself. We show that PMS stars spanning an age range from 0.1 to 3 Myr do notappear to conserve stellar angular momentum as they evolve down theirconvective tracks, but instead preserve the same range of periods even thoughthey have contracted by about a factor of three. This result seems to require amechanism that regulates the angular velocities of young stars. We discussseveral candidate mechanisms. The most plausible appears to be disk-locking,though most of our stars do not have (I-K) excesses suggestive of disks.However, a decisive test of this hypothesis requires a more sensitivediagnostic than the (I-K) excesses used here.Comment: 32 pages, 11 figures, accepted to A
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