1997PASP..109..221G

Using the 1-m telescope at Ritter Observatory, we took 36 observations of ζ² Coronae Borealis with a fiber-fed echelle spectrograph. From these observations, ζ² 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 ζ² CrB A and B and a 251 day period for the outer binary compsed of ζ² CrB AB and C. The inner binary is a double-lined spectroscopic binary composed of two B7 V stars. The inner binary`s center of mass (ζ² CrB AB) describes a long-period single-lined variation identified with the outer binary. The inner binary period is significantly shorter than the 12.5842 day period previously calculated by Abhyankar & Sarma (1966). 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 υ sin i's were calculated to be 46 ± 7 km.s^–1 for ζ² CrB A and 7.5 ± 2 km.s^–1 for ζ² CrB B. As ζ² CrB A and B have similar masses, their different rotational velocities make this system a sensitive test of synchronization theories.