H-BETA LINE-PROFILE VARIABILITY OF 7 SOUTHERN BE STARS
No Thumbnail Available
Date
1991
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The results of spectroscopic observations of six B0-B4e and one B7e stars at the Manuel Foster Observatory (Chile) during 1984-87 are reported. By means of photographic spectroscopy (20 angstrom/mm), equivalent widths, peak separations and V/R ratios were obtained for a total of 106 H-beta and 7 H-gamma line profiles. Emission episodes in H-beta were detected in 27 CMa and lambda Pav, lasting at least 5 months and 18 days respectively. Significant variations in the equivalent width of the H-beta emission line, W-beta, in time scales of months were found in kappa CMa, PP Car and QY Car. On the other hand alpha Ara and member-of PsA showed a relatively constant strength of emission. The variations in W-beta were interpreted as the cumulative effect of several individual ejections from the stellar surface with mass loss rates of the order of 10(-10) M./yr. A variable, centrally detached, disk-type H-beta emitting region with extensions r-beta less-than-or-equal-to 5r* and rotation law v(r) approximately 1/r, which implies outflow or inflow of matter rather than a stable Keplerian disk, was derived by comparing emission line profile data of all stars.
Description
Keywords
BE STARS, SPECTROSCOPY, EMISSION LINES