AAS 207th Meeting, 8-12 January 2006
Session 11 Binary Models and Parameters
Poster, Monday, 9:20am-7:00pm, January 9, 2006, Exhibit Hall

## [11.02] The Hyades Binary \theta2 Tauri: Optical Interferometry, Evolutionary Models, and Rapid Rotation

J. T. Armstrong (NRL), D. Mozurkewich (Seabrook Engineering), D. M. Peterson (SUNY Stony Brook), C. A. Hummel (ESO), G. C. Gilbreath (NRL)

Theta2 Tauri, a spectroscopic binary in the Hyades, has been observed spectroscopically and interferometrically over the past 10 years. Our orbit from the Mark III interferometer and the NPOI, combined with spectroscopic and parallax results, indicates that the binary components are less massive (2.15 ±0.13 and 1.88 ±0.11 solar masses) and/or brighter (0.48 ±0.05 and 1.61 ±0.08 mag in the V band) than predicted from some recent evolutionary models. However, both components are rapid rotators; as a result, the inclination of the rotation axis can affect both the colors and the magnitudes as seen from Earth. This effect may reconcile the absolute'' magnitude of the primary with the evolutionary models, but the secondary is still discrepant.