POSTER PAPER 4.05
On the Relationship Between Stellar Rotation and Radius in Young
Clusters
L. M. Rebull, S. C. Wolff, S. E. Strom, R. B. Makidon
Institute: National Research Council Resident Research Associate at
NASA/Jet Propulsion Laboratory
Institute: National Optical Astronomy Observatory
Institute: Space Telescope Science Institute
Contact Email: rebull@jpl.nasa.gov
Abstract:
We examine the early angular momentum history of stars in young clusters.
We reported (Rebull et al., in preparation), based on 197 photometric
periods in the Orion Flanking Fields and 83 photometric periods in NGC
2264, that PMS stars apparently do not conserve stellar angular momentum
(J) as they evolve down their convective tracks, but instead evolve at
nearly constant angular velocity (Omega). This result is inconsistent
with expectations that convective stars lacking disks should spin up as
they contract, but consistent with disk-locking models.
We have now mined the literature for data on 12 additional clusters
ranging in age from Orion to the Hyades, finding data for 1141 K & M
stars such that we can plot stellar rotational velocity vs. radius.
Taken together, these data reinforce our initial conclusion that
PMS stars spanning ages ~0.1--~10 Myr do not appear to spin up
in response to contraction, and further suggest that any spin up between
10 Myr and the ZAMS is modest (< 2x) at best.
Index Keywords: Rotation
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Manuscript submitted: 2001-Aug-30
"The Future of Cool-Star Astrophysics", 2003, Eds. A. Brown,
G. M. Harper, & T. R. Ayres.
Proceedings of 12th Cambridge Workshop on Cool Stars, Stellar Systems,
& The Sun,
© 2003 University of Colorado.