1 research outputs found
Kinematical structure of the circumstellar environments of galactic B[e]-type stars
High resolution line profiles are presented for selected forbidden and
permitted emission lines of a sample of galactic B[e]-type stars. The spectral
resolution corresponds to 5-7 km/s with the exception of some line profiles
which were observed with a resolution of 9-13 km/s. All Ha profiles are
characterized by a narrow split or single emission component with a width of
about 150-250 km/s (FWHM) and broad wings with a full width of ~1000-2000 km/s.
The Ha profiles can be classified into three groups: double-peaked profiles
representing the majority, single-peaked emission-line profiles, and normal P
Cygni-type profiles. The forbidden lines exhibit in most cases double-peaked
profiles. The split forbidden line profiles have peak separations of as little
as 10 km/s. The ratio of violet to red emission peak intensities, V/R, is
predominantly smaller or equal to 1. Theoretical profiles were calculated for
the optically thin case. A latitude-dependent stellar wind with a radial
expansion and a velocity decreasing from the pole to the equator was adopted.
In addition an equatorial dust ring with various optical depths was assumed.
This model can explain split lines and line asymmetries observed in some stars.
Moreover, the V/R ratios can be understood in terms of this model. The
comparison of the observed line profiles with the models thus confirms the
assumption of disk-like line-formation regions as commonly adopted for
B[e]-type stars.Comment: Astronomy & Astrophysics, in pres