Study of Hα regions in 120 Be-type stars
Abstract
DACs and SACs phenomena in Hα line of 120 Be stars In this study we apply the method proposed by Danezis et al. (2003, 2005) on the stellar spectrographs of 120 Be stars, and we examine the variations of the physical parameters, stated below, as a function of the spectral subtype and the luminosity class. We found that in the Be-type stellar atmospheres, there are two regions that can produce the Hα Satellite Absorption Components (SACs or DACs). The first one lies in the chromosphere and the second one in the cool extended envelope. With the above method we calculate: a) For the chromospheric absorption components: the optical depth as well as the rotational and radial velocities of the independent regions of matter which produce the main and the satellites components. b) For the emission and absorption components which are created in the cool extended envelope: the FWHM, the optical depth and the radial velocities of the independent regions of matter which produce the main and the satellites components.
- Publication:
-
UV Astronomy: Stars from Birth to Death
- Pub Date:
- July 2007
- Bibcode:
- 2007uasb.conf..131L
- Keywords:
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- UV astronomy;
- hot emission stars;
- H;
- DACs;
- SACs