Stochastic gravito-inertial modes discovered by CoRoT in the hot Be star HD 51452
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Stochastic gravito-inertial modes discovered by CoRoT in the hot Be star HD 51452

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Stochastic gravito-inertial modes discovered by CoRoT in the hot Be star HD 51452

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dc.contributor.author Neiner, C.
dc.contributor.author Floquet, M.
dc.contributor.author Samadi, R.
dc.contributor.author Espinosa-Lara, F.
dc.contributor.author Frémat, Y.
dc.contributor.author Mathis, S.
dc.contributor.author Leroy, B.
dc.contributor.author De Batz, B.
dc.contributor.author Rainer, M.
dc.contributor.author Poretti, E.
dc.contributor.author Mathias, P.
dc.contributor.author Guarro Fló, J.
dc.contributor.author Buil, C.
dc.contributor.author Ribeiro, J.
dc.contributor.author Alecian, E.
dc.contributor.author Andrade, L.
dc.contributor.author Briquet, M.
dc.contributor.author Diago Nebot, Pascual David
dc.contributor.author Emilio, M.
dc.contributor.author Fabregat Llueca, Juan
dc.contributor.author Gutiérrez Soto, Juan
dc.contributor.author Hubert, A.M.
dc.contributor.author Janot-Pacheco, E.
dc.contributor.author Martayan, C.
dc.contributor.author Semaan, T.
dc.contributor.author Suso, J.
dc.contributor.author Zorec, J.
dc.date.accessioned 2015-10-20T14:00:34Z
dc.date.available 2015-10-20T14:00:34Z
dc.date.issued 2012
dc.identifier.uri http://hdl.handle.net/10550/47829
dc.description.abstract Context.Be stars are rapidly rotating stars with a circumstellar decretion disk. They usually undergo pressure and/or gravity pulsation modes excited by the κ-mechanism, i.e. an effect of the opacity of iron-peak elements in the envelope of the star. In the Milky Way,p-modes are observed in stars that are hotter than or equal to the B3 spectral type, while g-modes are observed at the B2 spectral type and cooler.Aims.We observed a B0IVe star, HD 51452,with the high-precision, high-cadence photometric CoRoT satellite and high-resolution, ground-based HARPS and SOPHIE spectrographs to study its pulsations in great detail. We also used the lower resolution spectra available in the BeSS atabase. Methods.We analyzed the CoRoT and spectroscopic data with several methods: Clean -NG, Freq Find, and a sliding window method.We also analyzed spectral quantities, such as the violet over red (V/R) emission variations, to obtain information about the variation in the circumstellar environment. We calculated a stellar structure model with the ESTER code to test the various interpretation of the results.Results.We detect 189 frequencies of variations in the CoRoT light curve in the range between 0 and 4.5 c d−1. The main frequencies are also recovered in the spectroscopic data. In particular we find that HD 51452 undergoes gravito-inertial modes that are not in the domain of those excited by the κ-mechanism. We propose that these are stochastic modes excited in the convective zones and that at least some of them are a multiplet of r-modes (i.e. subinertial modes mainly driven by the Coriolis acceleration). Stochastically excited gravito-inertial modes had never been observed in any star, and theory predicted that their very low amplitudes would be undetectable even with CoRoT. We suggest that the amplitudes are enhanced in HD 51452 because of the very rapid stellar rotation.In addition, we find that the amplitude variations of these modes are related to the occurrence of minor outbursts.Conclusions.Thanks to CoRoT data, we have detected a new kind of pulsations in HD 51452, which are stochastically excited gravito-inertial modes, probably due to its very rapid rotation. These modes are probably also present in other rapidly rotating hot Be stars.
dc.language.iso eng
dc.relation.ispartof Astronomy and Astrophysics, 2012, vol. 546, p. A47
dc.rights.uri info:eu-repo/semantics/openAccess
dc.source Neiner, C. Floquet, M. Samadi, R. Espinosa Lara, F. Frémat, Y. Mathis, S. Leroy, B. De Batz, B. Rainer, M. Poretti, E. Mathias, P. Guarro Fló, J. Buil, C. Ribeiro, J. Alecian, E. Andrade, L. Briquet, M. Diago, P. D. Emilio, M. Fabregat, J. Gutiérrez-Soto, J. Hubert, A.-M. Janot-Pacheco, E. Martayan, C. Semaan, T. Suso, J. Zorec, J. 2012 Stochastic gravito-inertial modes discovered by CoRoT in the hot Be star HD 51452 Astronomy and Astrophysics 546 A47
dc.subject Ciència Ensenyament
dc.subject Partícules (Física nuclear)
dc.title Stochastic gravito-inertial modes discovered by CoRoT in the hot Be star HD 51452
dc.type info:eu-repo/semantics/article
dc.date.updated 2015-10-20T14:00:35Z
dc.identifier.idgrec 107397

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