Betelgeuse: Giant convection cells

Authors
Citation
Df. Gray, Betelgeuse: Giant convection cells, PUB AST S P, 113(789), 2001, pp. 1378-1385
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC
ISSN journal
0004-6280 → ACNP
Volume
113
Issue
789
Year of publication
2001
Pages
1378 - 1385
Database
ISI
SICI code
0004-6280(200111)113:789<1378:BGCC>2.0.ZU;2-7
Abstract
Spectroscopic observations of the M supergiant star Betelgeuse were taken a t the Elginfield Observatory over 17 months in the 1999-2000 observing seas ons in order to search for giant convection cells. Although the photospheri c spectral lines show some temporal variations, mainly in their depths (con sistent with a previously study), the Doppler shift distribution inferred f rom them is remarkably stable. The spectral lines show characteristic macro turbulence dispersion similar to 15 km s(-1) and cover a full span of +/-50 -60 km s(-1). The widths of the lines show occasional as well as longer ter m changes of a few percent but no evidence for giant convection cells. Thes e spectroscopic observations are more consistent with a classical picture o f nonthermal photospheric velocities in which large numbers of convection c ells appear on the stellar disk at all times.