Article (Scientific journals)
A search for pulsations in the HgMn star HD 45975 with CoRoT photometry and ground-based spectroscopy
Morel, Thierry; Briquet, Maryline; Auvergne, M. et al.
2014In Astronomy and Astrophysics, 561, p. 35
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Keywords :
asteroseismology; stars: oscillations; stars: chemically peculiar; stars: abundances; stars: individual: HD 45975; starspots
Abstract :
[en] The existence of pulsations in HgMn stars is still being debated. To provide the first unambiguous observational detection of pulsations in this class of chemically peculiar objects, the bright star HD 45975 was monitored for nearly two months by the CoRoT satellite. Independent analyses of the light curve provide evidence of monoperiodic variations with a frequency of 0.7572 d[SUP]-1[/SUP] and a peak-to-peak amplitude of ~2800 ppm. Multisite, ground-based spectroscopic observations overlapping the CoRoT observations show the star to be a long-period, single-lined binary. Furthermore, with the notable exception of mercury, they reveal the same periodicity as in photometry in the line moments of chemical species exhibiting strong overabundances (e.g., Mn and Y). In contrast, lines of other elements do not show significant variations. As found in otherHgMn stars, the pattern of variability consists in an absorption bump moving redwards across the line profiles. We argue that the photometric and spectroscopic changes are more consistent with an interpretation in terms of rotational modulation of spots at the stellar surface. In this framework, the existence of pulsations producing photometric variations above the ~50 ppm level is unlikely in HD 45975. This provides strong constraints on the excitation/damping of pulsation modes in this HgMn star. 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. This work is based on observations collected at La Silla and Paranal Observatories, ESO (Chile), with the HARPS and UVES spectrographs at the 3.6-m and very large telescopes, under programmes LP185.D-0056 and 287.D-5066. It is also based on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. Based on observations obtained with the HERMES spectrograph, which is supported by the Fund for Scientific Research of Flanders (FWO), Belgium, the Research Council of K.U. Leuven, Belgium, the Fonds National de la Recherche Scientifique (FNRS), Belgium, the Royal Observatory of Belgium, the Observatoire de Genève, Switzerland, and the Thüringer Landessternwarte Tautenburg, Germany.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Morel, Thierry  ;  Université de Liège - ULiège > GAPHE : Astrophysique observationnelle (sol et espace)
Briquet, Maryline ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Auvergne, M.;  LESIA, Observatoire de Paris, CNRS, 5 place J. Janssen, 92190, Meudon, France
Alecian, G.;  LUTH, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place J. Janssen, 92190, Meudon, France
Ghazaryan, S.;  LUTH, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place J. Janssen, 92190, Meudon, France ; Byurakan Astrophysical Observatory, Aragatzotn Province, 0213, Byurakan, Armenia
Niemczura, E.;  Astronomical Institute, Wrocław University, Kopernika 11, 51-622, Wrocław, Poland
Fossati, L.;  Argelander-Institut für Astronomie der Universität Bonn, auf dem Hügel 71, 53121, Bonn, Germany
Lehmann, H.;  Thüringer Landessternwarte Tautenburg (TLS), Sternwarte 5, 07778, Tautenburg, Germany
Hubrig, S.;  Leibniz-Institut für Astrophysik Potsdam (AIP), an der Sternwarte 16, 14482, Potsdam, Germany
Ulusoy, C.;  College of Graduate Studies, University of South Africa, PO Box 392, UNISA 0003, Johannesburg, South Africa
Damerdji, Y.;  CRAAG, Alger
Rainer, M.;  INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807, Merate, LC, Italy
Poretti, E.;  INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807, Merate, LC, Italy
Borsa, F.;  INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807, Merate, LC, Italy ; Dipartimento di Scienza e Alta Tecnologia, Università dell'Insubria, via Valleggio 11, 22100, Como, Italy
Scardia, M.;  INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807, Merate, LC, Italy
Schmid, V. S.;  Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
Van Winckel, H.;  Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
De Smedt, K.;  Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
Pápics, P. I.;  Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
Gameiro, J. F.;  Centro de Astrofísica e Faculdade de Ciências da Universidade do Porto, rua das Estrelas, 4150-762, Porto, Portugal
Waelkens, C.;  Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
Fagas, M.;  Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286, Poznań, Poland
Kamiński, K.;  Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286, Poznań, Poland
Dimitrov, W.;  Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286, Poznań, Poland
Baglin, A.;  LUTH, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place J. Janssen, 92190, Meudon, France
Michel, E.
Dumortier, L.;  Royal Observatory of Belgium, 3 avenue Circulaire, 1180, Brussels, Belgium
Frémat, Y.;  Royal Observatory of Belgium, 3 avenue Circulaire, 1180, Brussels, Belgium
Hensberge, H.;  Royal Observatory of Belgium, 3 avenue Circulaire, 1180, Brussels, Belgium
Jorissen, A.;  Institut d'Astronomie et d'Astrophysique, Université libre de Bruxelles, Boulevard du Triomphe CP 226, 1050, Bruxelles, Belgium
Van Eck, S.;  Institut d'Astronomie et d'Astrophysique, Université libre de Bruxelles, Boulevard du Triomphe CP 226, 1050, Bruxelles, Belgium)
More authors (21 more) Less
Language :
English
Title :
A search for pulsations in the HgMn star HD 45975 with CoRoT photometry and ground-based spectroscopy
Publication date :
01 January 2014
Journal title :
Astronomy and Astrophysics
ISSN :
0004-6361
eISSN :
1432-0746
Publisher :
EDP Sciences, Les Ulis, France
Volume :
561
Pages :
35
Peer reviewed :
Peer Reviewed verified by ORBi
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