Soft x-ray observations of the early b-giants beta and epsilon CMA

Abstract

The study reports observations performed with the PSPC on board the Roentgensatellit (ROSAT) of the two nearby giant stars Beta CMa (B1 II-III) and Epsilon CMa (B2 II). Upper limits in the region of +/- 10 percent can be set on the variation of the 0.1-0.4 keV and 0.5-2.0 keV fluxes from Beta CMa. By attributing the soft X-ray emission to an outer zone of hot shocked gas enclosing the cool inner wind responsible for observed UV blueshifted absorption features, it is estimated that the mass loss for Beta and Epsilon CMa, respectively, are (6 +/- 2) x 10 exp 9 and (8 +/- 2) x 10 exp -9 solar mass/yr.