Goddard-HRS observations of variability in the RS CVn system V711 Tau (HR 1099)

Abstract

Through examination of line profile asymmetries and their phase-dependent behavior at high-resolution and high S/N we can determine the spatial structure (i.e., size, location, temperature, magnetic field distribution) of atmospheric inhomogeneities on stars other than the Sun (Vogt & Penrod 1983; Walter et al. 1987; Neff et al. 1989). In an effort to simultaneously probe several lines in addition to Mg II we observed the RS CVn V711 Tau (HR 1099, Prot = 2.d8, G5 IV + K1 IV) with the GHRS in the fall of 1993. Ultraviolet observations were obtained with HST's GHRS over a one week interval beginning 1993 September 14. Full details can be found in Dempsey et al. (1996; see also Wood et al. 1995). In this paper we present results of detailed modeling of the the Mg II emission profiles. Line fluxes and profile models for the emission lines were calculated using least-squares gaussian fits as described in Neff et al. (1989).