Ultraviolet observations of 27 CMa, pi AQR and 48 Lib.

Abstract

An analysis of 27 CMa, Pi Aqr, and 48 Lib, Be stars and V/R variables is discussed to determine the physical conditions and the gaseous structure surrounding the stars. On the basis of two different types of absorption lines the narrow and deep, and the broad and shallow profiles, the gaseous structure is divided into two regions: (1) a geometrically thin region that rotates with the stars, and exhibits higher ionization temperatures than the temperature of the radiation field of the stars, and expands with velocities not higher than the escape velocity of a normal star; and (2) an extended cold region which does not rotate with the star, with expansion velocities decreasing to the values of the radial velocities of the interstellar line.