Article (Scientific journals)
Variability in the CoRoT photometry of three hot O-type stars. HD 46223, HD 46150, and HD 46966
Blomme, R.; Mahy, Laurent; Catala, C. et al.
2011In Astronomy and Astrophysics, 533, p. 4
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Keywords :
stars: variables: general; stars: early-type; stars: oscillations; stars: individual: HD 46223; stars: individual: HD 46150; stars: individual: HD 46966
Abstract :
[en] Context. The detection of pulsational frequencies in stellar photometry is required as input for asteroseismological modelling. The second short run (SRa02) of the CoRoT mission has provided photometric data of unprecedented quality and time-coverage for a number of O-type stars. <BR /> Aims: We analyse the CoRoT data corresponding to three hot O-type stars, describing the properties of their light curves and search for pulsational frequencies, which we then compare to theoretical model predictions. <BR /> Methods: We determine the amplitude spectrum of the data, using the Lomb-Scargle and a multifrequency HMM-like technique. Frequencies are extracted by prewhitening, and their significance is evaluated under the assumption that the light curve is dominated by red noise. We search for harmonics, linear combinations, and regular spacings among these frequencies. We use simulations with the same time sampling as the data as a powerful tool to judge the significance of our results. From the theoretical point of view, we use the MAD non-adiabatic pulsation code to determine the expected frequencies of excited modes. <BR /> Results: A substantial number of frequencies is listed, but none can be convincingly identified as being connected to pulsations. The amplitude spectrum is dominated by red noise. Theoretical modelling shows that all three O-type stars can have excited modes, but the relation between the theoretical frequencies and the observed spectrum is not obvious. <BR /> Conclusions: The dominant red noise component in the hot O-type stars studied here clearly points to a different origin than the pulsations seen in cooler O stars. The physical cause of this red noise is unclear, but we speculate on the possibility of sub-surface convection, granulation, or stellar wind inhomogeneities being responsible. The CoRoT space mission was developed and is operated by the French space agency CNES, with participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany and Spain.Tables 2-4 are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/533/A4">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/533/A4</A>
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Blomme, R.;  Royal Observatory of Belgium, Ringlaan 3, 1180, Brussel, Belgium
Mahy, Laurent ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Sciences spatiales
Catala, C.;  LESIA, UMR 8109, Observatoire de Paris, 5 place Jules Janssen, 92195, Meudon Cedex, France
Cuypers, J.;  Royal Observatory of Belgium, Ringlaan 3, 1180, Brussel, Belgium
Gosset, Eric ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE)
Godart, Mélanie ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Montalban Iglesias, Josefa ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Ventura, P.;  INAF, Osservatorio Astronomico di Roma, via Frascati 33, 00040, Monteporzio Catone (Roma), Italy
Rauw, Grégor  ;  Institut d'Astrophysique et de Géophysique, University of Liège, Bât. B5C, Allée du 6 Août 17, 4000, Liège, Belgium
Morel, Thierry  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE)
Degroote, P.;  Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
Aerts, C.;  Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium ; Department of Astrophysics, IMAPP, University of Nijmegen, PO Box 9010, 6500 GL, Nijmegen, The Netherlands
Noels-Grötsch, Arlette ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Michel, E.
Baudin, F.;  Institut d'Astrophysique Spatiale (IAS), Bâtiment 121, Université Paris-Sud, 91405, Orsay Cedex, France
Baglin, A.;  LESIA, UMR 8109, Observatoire de Paris, 5 place Jules Janssen, 92195, Meudon Cedex, France
Auvergne, M.;  LESIA, UMR 8109, Observatoire de Paris, 5 place Jules Janssen, 92195, Meudon Cedex, France
Samadi, R.;  LESIA, UMR 8109, Observatoire de Paris, 5 place Jules Janssen, 92195, Meudon Cedex, France
More authors (8 more) Less
Language :
English
Title :
Variability in the CoRoT photometry of three hot O-type stars. HD 46223, HD 46150, and HD 46966
Publication date :
01 September 2011
Journal title :
Astronomy and Astrophysics
ISSN :
0004-6361
eISSN :
1432-0746
Publisher :
EDP Sciences, Les Ulis, France
Volume :
533
Pages :
4
Peer reviewed :
Peer Reviewed verified by ORBi
Commentary :
http://de.arxiv.org/abs/1107.0267
Available on ORBi :
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