Rotation/saturation/dynamos -- Oral Presentation
Rotation of Low Mass Pre-Main Sequence Stars
William Herbst, Wesleyan University
Photometric monitoring campaigns have yielded rotation periods,
with a typical accuracy of about 1%, for nearly 2000 pre-main sequence
stars of low mass in nearby clusters and associations. When combined
with stellar radii, these data yield the average specific angular
momentum (j) of the surface layer of each star. There are now sufficient
data that we can assess on a quantitative statistical basis how the
frequency distribution of j depends on mass and age. Empirical results
will be presented and an interpretation in terms of the canonical theory
of disk locking proposed. The implications of these results for accretion
disk lifetimes and for the interpretation of X-ray observations will be
briefly summarized.