Dynamical Masses for Pre-Main-Sequence Stars: A Preliminary Physical Orbit for V773 Tau A

We report on interferometric and radial velocity observations of the double-lined 51 day period binary (A) component of the quadruple pre-main-sequence (PMS) system V773 Tau. With these observations we have estimated preliminary visual and physical orbits of the V773 Tau A subsystem. Among other parameters, our orbit model includes an inclination of 66.0deg +- 2.4deg and allows us to infer the component dynamical masses and system distance. In particular, we find component masses of 1.54 +- 0.14 and 1.332 +- 0.097 M for the Aa (primary) and Ab (secondary) components, respectively. Our modeling of the subsystem component spectral energy distributions finds temperatures and luminosities consistent with previous studies and, coupled with the component mass estimates, allows for comparison with PMS stellar models in the intermediate-mass range. We compare V773 Tau A component properties with several popular solar composition models for intermediate-mass PMS stars. All models predict masses consistent to within 2 s of the dynamically determined values, although some models predict values that are more consistent than others.