Spectral types and rotational velocities of the brighter Be stars and A-F type shell stars. (original) (raw)

NASA/ADS

Abstract

Spectral types and rotational velocities have been estimated for the Oe, Be, and A-F type shell stars brighter than ∼6.0 mag over the entire sky. Spectra of the 183 program stars were obtained at the Lowell Observatory and the Cerro Tololo Inter-American Observatory on fine grain, high contrast emulsion to enhance the visibility of faint and diffuse features. The distribution of stars by spectral type shows a single maximum at B2, with a very steep decline to earlier spectral types and a gradual decline to later B types. At least as many luminosity class III and Iv stars as main-sequence objects were found among the stars which show the Be phenomenon, in agreement with earlier work on Be stars in clusters and in visual binary systems. Mean values of the rotational velocity (υ sin i) show little variation with either spectral type or luminosity class among the Be stars. Descriptions of the spectra plus a summary of recent observations of the program stars are given. An interesting sidelight is that about one-fourth of the stars show Fe ii emission and that the V/R characteristics of this emission are not always the same as that of the Balmer emission components for a given star.

Publication:

The Astrophysical Journal Supplement Series

Pub Date:

September 1982

DOI:

10.1086/190820

Bibcode:

1982ApJS...50...55S

Keywords: