1978/12/01 by B. W. Bopp, J. C. Talcott, John C. Talcott
Physics and Astronomy · #Astronomy and Astrophysical Research #Stellar, planetary, and galactic studies #Gamma-ray bursts and supernovae
paper · doi:10.1086/112355
We report the results of a survey of V7 11 Tau (HR 1099), UX Ari, and 26 other RS CVn and Ca II emission binaries for Ha emission. A total of six stars show Ha continuously or sporadically in emission while the remainder show pure absorption profiles at 1-A resolution. Observations of UX Ari during 19761977 indicate that the equivalent width (EW) of the emission is correlated with the orbital phase with maximum strength occurring near = O .6. At this same epoch, Hall found the phase of photometric minimum to be O .8 in late 1976 moving to 0 .7 in early 1977. Another RS CVn binary, V71 1 Tau, has been observed for three years and intensively during two major radio flares. Though Ha is enhanced by a factor of two to three during radio outbursts, the EW in HR 1099 is not correlated with orbital phase and no long-term variations are apparent. Four stars show sporadic emission: HD 86590, HK Lac, AR Lac, and SZ Psc.