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Shell Stars in the Geneva Photometric System

Published online by Cambridge University Press:  23 September 2016

B. Hauck
B. Hauck*
Affiliation:
Institut d'Astronomie de l'Université de Lausanne, and Observatoire de Genève, 1290 Chavannes-des-Bois, Switzerland

Extract

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L. Divan (1979) showed that the Balmer jump is greater in a Be-shell star than in a star of same spectral type and we will consider if this property is also present in A and F-shell stars by studying their data in the Geneva photometric system. Two photometric parameters in this system are correlated with the Balmer jump: d=(U-Bl) -1.430 (B1-B2) and Δ=(U-B2) -0.832 (B2-G). In addition to the Balmer jump, Δ is also sensitive to blanketing. Both parameters are reddening free. A study of the Be stars of luminosity class V or IV classified by Slettebak (1982) shows that, in a d vs Δ diagram, they are in the area of main sequence stars or a little above, while the majority of Be-shell stars are above the Be star sequence. Pleione is well known for presenting a Be phase followed by a shell phase.

Type
V. Evolutionary Status of Be Stars
Information
International Astronomical Union Colloquium , Volume 92: Physics of Be Stars , August 1987 , pp. 523 - 525
Copyright
Copyright © Cambridge University Press 1987

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