DISCOVERY OF A PRE-MAIN-SEQUENCE SPECTROSCOPIC BINARY - V773 TAURI

A series of spectra of V773 Tau obtained during a seven night observing run at Kitt Peak National Observatory (KPNO) in 1993 December revealed a double-lined structure. A period of several weeks is indicated by those spectra, which are best fit by a K2 V plus K5 V model. Further observations in 1994 March at Penn State's Black Moshannon Observatory (BMO), 1994 December and 1995 January at KPNO, and three archival KPNO spectra from 1988 January and 1992 November constrain the period to be 51.075 +/- 0.018 days. The orbit of V773 Tau is eccentric and is seen at moderately high inclination, but probably not high enough for eclipses to occur. HR diagram placement and recent calculations of pre-main-sequence evolution suggest a mass ratio of about 1.78. While highly uncertain, this is higher than the dynamical mass ratio, q = 1.32 +/- 0.06. It is suggested that VLBI structures previously reported may simply be emission from both stars and possible RS CVn-like interaction, rather than huge loop structures. (C) 1995 American Astronomical Society.