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Short-term Periodicity in the Pole-on Be Star υ Cyg

Published online by Cambridge University Press:  12 April 2016

M. Floquet ,
C. Neiner ,
A.M. Hubert ,
E. Janot-Pacheco  and
N.V. Leister
M. Floquet
Affiliation:
Dasgal, UMR8633 du CNRS, Observatoire de Paris-Meudon, F-92195 Meudon, France
C. Neiner
Affiliation:
Dasgal, UMR8633 du CNRS, Observatoire de Paris-Meudon, F-92195 Meudon, France
A.M. Hubert
Affiliation:
Dasgal, UMR8633 du CNRS, Observatoire de Paris-Meudon, F-92195 Meudon, France
E. Janot-Pacheco
Affiliation:
Instituto Astronomico e Geofisico, Universidade de Sao Paulo, Caixa Postal 3386, 01060-970 Sao Paulo, Brazil
N.V. Leister
Affiliation:
Instituto Astronomico e Geofisico, Universidade de Sao Paulo, Caixa Postal 3386, 01060-970 Sao Paulo, Brazil

Abstract

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The pole-on Be star υ Cyg (HD 202904) displayed with Hipparcos photometry a strong long-lived outburst between 1989 and 1993. High S/N spectroscopic observations were obtained in August-September 1998. The photospheric λ6678 line is strongly perturbed by variable outer V and R emission components and is itself highly variable.

All the studied quantities (profiles, EW, radial velocity of the line centroid, V and R emission components, V/R ratio) are dominated by ν = 1.5 c/d frequency. The first harmonic (ν = 3.0 c/d) is also detected in the central part of the profile. In the nrp frame, this pair of frequencies corresponds to a low degree sectorial g-mode l = |m| = 2. Moreover mid-term variations are superimposed to short ones.

Type
3. Periodic Variations
Information
International Astronomical Union Colloquium , Volume 175: The Be Phenomenon in Early-Type Stars , 2000 , pp. 260 - 263
Copyright
Copyright © Astronomical Society of the Pacific 2000

References

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