Session 43 - Binary Stars.
Display session, Tuesday, January 16
North Banquet Hall, Convention Center

## [43.03] Double Star Astronomy with Optical Interferometers

J. T. Armstrong (NRL), C. A. Hummel (USRA)

We review results from optical interferometric observations of spectroscopic binaries obtained over the last several years. Orbits with semi-major axes as small as 3 milliarcseconds have been resolved, the magnitude difference between components has been measured, and component diameters have been even determined in some cases (e.g.\ for Capella and \zeta Aurigae). Important astrophysical information on stellar masses, luminosities, and effective temperatures has been derived from the data and compared to stellar evolution models. We recall one of the most successful first-generation'' interferometers, the Mark III interferometer on Mt.\ Wilson, California, and report on progress with instruments of the next generation. Among the latter is the USNO/NRL Navy Prototype Optical Interfero\-meter, which has seen first fringes in 1994 and will upon completion of its some 450 m long baselines be able to push observations into the realm of interacting binaries.