AAS 205th Meeting, 9-13 January 2005
Session 16 Ae Be and T Tauri Stars
Poster, Monday, January 10, 2005, 9:20am-6:30pm, Exhibit Hall

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[16.03] Modeling Period Distribution of T Tauri Stars

R. S. Yamada, A. A. Esin (Harvey Mudd College)

Observations of low-mass T Tauri stars in the Orion Nebula Cluster have shown evidence for a bimodal distribution. Stars with M > 0.25 M\odot exhibit a population peak at rotational period of order 8 days, while lower mass stars do not. Magnetic locking between the star and the circumstellar disk has been proposed as an explanation for the peak in the distribution of higher mass stars. To test this hypothesis, we examined a steady-state accretion model, in which the torques on a T Tauri star (from accretion, stellar wind, and magnetic disk braking) balance to produce the 8-day rotation period. We explored a range of plausible values for the accretion rate, \dot{M}, and magnetic field strengths, B, for stars with M < 0.5 M\odot. Our preliminary results indicate that a steady-state model with \dot{M} ~10-7-10-8 M\odot/yr and B ~0.5-1\,kG (values typically quoted in the literature) can not explain the observed period distribution of T Tauri stars.

This work was supported by the Beckman award from Harvey Mudd College.

The author(s) of this abstract have provided an email address for comments about the abstract: ryamada@hmc.edu

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© 2004. The American Astronomical Society.