IUE and ground-based spectroscopic observations of the S Dor-type LMCvariable R 71 during minimum state.

Abstract

Using the IUE satellite, high resolution UV spectrograms are obtained of the S Dor type variable R 71 in the LMC. The IUE observations are supplemented by coordinated ground-based high dispersion spectroscopy and photometric observations. For the expanding envelope, a surprisingly low temperature of only about 6000 K and an apparently decelerated velocity field with a maximum outflow velocity of approximately 127 km/sec are found. The minimum state mass loss rate is of the order of 3 x 10 to the -7 solar mass/year. The results support the suggestion that the visual light variations of the S Dor type variables are produced by strong density variations of the expanding envelopes of these objects.