1998ApJ...509L..45K

We report new observations of the RS Canum Venaticorum binary star TZ Trianguli with the Palomar Testbed Interferometer. The object exhibits fringe visibilities below the measured instrumental visibility, which indicates that it is partially resolved at the angular scales detectable by our observations. In most respects, the visibility data are consistent with the predictions of previous photometric and spectroscopic measurements. Comparison with a simple binary star model reveals clear evidence of orbital motion with the expected period and phase. The evolved primary star is resolved, and its size is found to be close to that derived by Hall in 1990. The relative brightness of the secondary star appears to be somewhat smaller than expected at the 2.2 µm wavelength of the new observations. We conclude that the interferometric observations, which represent a new and nearly independent test of the models for this binary star, essentially confirm the spectroscopic results.