Volume 386, Number 3, May II 2002
|Page(s)||1009 - 1018|
|Section||Stellar structure and evolution|
|Published online||15 May 2002|
The outer atmosphere of the M-type supergiant α Orionis: K I 7699 Å emission
GRAAL Université de Montpellier II, 34095 Montpellier Cedex 5, France
2 Department of Astronomy, University of Texas at Austin, Austin, TX 78712-1083, USA
Corresponding author: B. Plez, firstname.lastname@example.org
Accepted: 1 March 2002
Spatially-resolved high-resolution long-slit spectra of Betelgeuse's circumstellar shell are described for a spectral window centered on the 7699 Å resonance line of neutral potassium. The K i emission from resonance fluorescent scattering of photospheric photons which is mapped out to 50 arcsec from the star is approximately spherically symmetric with a brightness decreasing as , where r is the radial distance from the star. Our measurements together with the earlier theoretical interpretation by Rodgers & Glassgold suggest that the mass loss rate is about y-1. The K i emission is far from homogeneous: intensity inhomogeneities are seen down to the seeing limit of about 1 arcsec and the velocity resolution of about 2 km s-1. There is clear evidence for a thin shell of 50 arcsec radius. This is identified with the weaker circumstellar absorption component known as S2. Estimates are made of the density of K atoms in this shell ( cm-3).
Key words: stars: circumstellar matter / stars: individual: Betelgeuse / stars: supergiants / stars: winds, outflows
© ESO, 2002
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.