Session 77 - Binary Stars.
Display session, Wednesday, January 15
Metropolitan Ballroom,

## [77.02] Zeta^2 Coronae Borealis, a Spectroscopic Triple System Including an Asynchronous Close Binary

C. L. Mulliss, K. D. Gordon (U. Toledo)

Using the 1-m telescope at Ritter Observatory, 36 observations of \zeta^2 Coronae Borealis were taken with a fiber-fed échelle spectrograph. From these observations, \zeta^2 CrB was found to be a triple system and a new spectroscopic orbit was calculated. This orbit has two periods, a 1.72357 day period for the inner binary composed of \zeta^2 CrB A amp; B and a 251 day period for the outer binary composed of \zeta^2 CrB AB amp; C. The inner binary period is significantly shorter than the 12.5842 day period previously calculated by Abhyankar amp; Sarma (1966, MNRAS, 133, 437). The inner binary possesses an essentially circular orbit (e = 0.01) while the outer binary has an eccentric orbit (e = 0.48). From the widths of their Si II 6371 Å\ lines, the v\sin i's were calculated to be 42--51 km s^-1 for \zeta^2 CrB A and 7--8 km s^-1 for \zeta^2 CrB B. As \zeta^2 CrB A amp; B have similar masses, their different rotational velocities make this system a sensitive test of synchronization theories.