Article (Scientific journals)
The CoRoT target HD 49933 . I. Effect of the metal abundance on the mode excitation rates
Samadi, R.; Ludwig, H*-G; Belkacem, Kevin et al.
2010In Astronomy and Astrophysics, 509, p. 15
Peer Reviewed verified by ORBi
 

Files


Full Text
samadiaa11867-09.pdf
Publisher postprint (202.12 kB)
Download

All documents in ORBi are protected by a user license.

Send to



Details



Keywords :
convection; turbulence; stars: oscillations; stars: individual: HD 49933; Sun: helioseismology
Abstract :
[en] Context. Solar-like oscillations are stochastically excited by turbulent convection at the surface layers of the stars. <BR /> Aims: We study the role of the surface metal abundance on the efficiency of the stochastic driving in the case of the CoRoT target HD 49933. <BR /> Methods: We compute two 3D hydrodynamical simulations representative - in effective temperature and gravity - of the surface layers of the CoRoT target HD 49933, a star that is rather metal poor and significantly hotter than the Sun. One 3D simulation has a solar metal abundance, and the other has a surface iron-to-hydrogen, [Fe/H], abundance ten times smaller. For each 3D simulation we match an associated global 1D model, and we compute the associated acoustic modes using a theoretical model of stochastic excitation validated in the case of the Sun and α Cen A. <BR /> Results: The rate at which energy is supplied per unit time into the acoustic modes associated with the 3D simulation with [Fe/H] = -1 is found to be about three times smaller than those associated with the 3D simulation with [Fe/H] = 0. As shown here, these differences are related to the fact that low metallicity implies surface layers with a higher mean density. In turn, a higher mean density favors smaller convective velocities and hence less efficient driving of the acoustic modes. <BR /> Conclusions: Our result shows the importance of taking the surface metal abundance into account in the modeling of the mode driving by turbulent convection. A comparison with observational data is presented in a companion paper using seismic data obtained for the CoRoT target HD 49933. The CoRoT space mission, launched on December 27, 2006, has been developped and is operated by CNES, with the contribution of Austria, Belgium, Brasil, ESA, Germany and Spain.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Samadi, R.;  Observatoire de Paris, LESIA, CNRS UMR 8109, Université Pierre et Marie Curie, Université Denis Diderot, 5 pl. J. Janssen, 92195 Meudon, France
Ludwig, H*-G;  Observatoire de Paris, GEPI, CNRS UMR 8111, 5 pl. J. Janssen, 92195 Meudon, France
Belkacem, Kevin ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Goupil, M. J.;  Observatoire de Paris, LESIA, CNRS UMR 8109, Université Pierre et Marie Curie, Université Denis Diderot, 5 pl. J. Janssen, 92195 Meudon, France
Dupret, Marc-Antoine ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Language :
English
Title :
The CoRoT target HD 49933 . I. Effect of the metal abundance on the mode excitation rates
Publication date :
01 January 2010
Journal title :
Astronomy and Astrophysics
ISSN :
0004-6361
eISSN :
1432-0746
Publisher :
EDP Sciences, Les Ulis, France
Volume :
509
Pages :
15
Peer reviewed :
Peer Reviewed verified by ORBi
Commentary :
http://de.arxiv.org/abs/0910.4027
Available on ORBi :
since 12 November 2010

Statistics


Number of views
37 (0 by ULiège)
Number of downloads
52 (1 by ULiège)

Scopus citations®
 
27
Scopus citations®
without self-citations
11
OpenCitations
 
26

Bibliography


Similar publications



Contact ORBi