Article (Scientific journals)
Theoretical Aspects of g-mode Pulsations in gamma Doradus Stars
Dupret, Marc-Antoine; Grigahcène, A.; Garrido, R. et al.
2006In Memorie della Societa Astronomica Italiana, 77, p. 366
 

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Keywords :
Stars: oscillations; Convection; Stars: interiors; Stars: variables: general
Abstract :
[en] gamma Dor stars are main sequence variable A-F stars whose long periods (between 0.35 and 3 days) correspond to high-order gravity modes pulsation. Most of them are multiperiodic. We will concentrate here on two theoretical aspects of these stars. First, an analysis of the driving mechanism of the gamma Dor g-modes is presented, using the linear Time-Dependent Convection (TDC) treatment of Gabriel \cite{Gabriel1996} and Grigahcène et al. \cite{Grigahcene}. This driving is due to a periodic flux blocking mechanism at the base of their convective envelope. The location of the blue and red edges of their instability strip as well as the periods range of their observed modes is explained by the balance between this driving mechanism and radiative damping in the g-mode cavity. Secondly, the multi-color photometric amplitude ratios and the phase differences between the light and velocity curves are considered. It is shown that the agreement between theory and observations obtained with TDC models is much better than with Frozen Convection (FC) models. The theoretical analysis of these observables makes the photometric identification of the degree l of the modes possible and gives constraints on the characteristics of the convective envelope of these stars. Finally, the attractive potential of gamma Dor stars as targets for asteroseismology is considered.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Dupret, Marc-Antoine ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique
Grigahcène, A.;  Instituto de Astrofísica de Andalucía-CSIC, Apartado 3004, 18080 Granada, Spain ; CRAAG - Algiers Observatory BP 63 Bouzareah 16340, Algiers, Algeria
Garrido, R.;  Instituto de Astrofísica de Andalucía-CSIC, Apartado 3004, 18080 Granada, Spain
De Ridder, J.;  Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, 3001 Leuven, Belgium
Moya, A.;  Observatoire de Paris, LESIA, CNRS UMR 8109, 92195 Meudon, France
Suárez, J.-C.;  Instituto de Astrofísica de Andalucía-CSIC, Apartado 3004, 18080 Granada, Spain
Scuflaire, Richard ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Evol. et stabilité des étoiles et des amas d'étoiles (ESEA)
Gabriel, Maurice ;  Département d'astrophys., géophysique et océanographie (AGO)
Goupil, Marie-José;  Observatoire de Paris, LESIA, CNRS UMR 8109, 92195 Meudon, France
Language :
English
Title :
Theoretical Aspects of g-mode Pulsations in gamma Doradus Stars
Publication date :
2006
Journal title :
Memorie della Societa Astronomica Italiana
ISSN :
0037-8720
Publisher :
Societa Astronomica Italiana, Milano, Italy
Volume :
77
Pages :
366
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