AAS 199th meeting, Washington, DC, January 2002
Session 6. Binary Stars
Display, Monday, January 7, 2002, 9:20am-6:30pm, Exhibit Hall

## [6.16] The Orbit of \theta2 Tauri from Long Baseline Optical Interferometry

J. T. Armstrong, D. Mozurkewich (Naval Research Laboratory), A. R. Hajian (US Naval Observatory), R. N. Thessin (Caltech), D. M. Peterson (SUNY Stony Brook)

We present the visual orbit of the Hyades spectroscopic binary \theta2 Tauri from observations with the Mark III Optical Interferometer and the Navy Prototype Optical Interferometer. Combining the visual orbit with the secular parallax from Hipparcos data (de Bruijne et al. 2001, A&A, 367, 111) produces a total mass \Sigma M of the system of 4.02+0.23-0.20 solar masses. Combining the visual orbit with three recent spectroscopic orbits produces three less-precise and somewhat discordant estimates of \Sigma M. We use the spectroscopic orbit that best agrees with \Sigma M from the parallax---Torres, Stefanik, & Latham (1997, ApJ, 485, 167)---to allocate \Sigma M between the two components. The result is 2.14 and 1.87 solar masses, with uncertainties (for the masses taken individually) of about 0.13 solar masses, somewhat below the masses expected from some recent isochrones. The mass estimates are somewhat correlated, in the sense that accepting a mass at the upper end of the error bar f

The author(s) of this abstract have provided an email address for comments about the abstract: tarmstr@rsd.nrl.navy.mil