Title : Ground-based observations of the beta Cephei CoRoT main target HD 180 642: abundance analysis and mode identification Language : English Author, co-author : Briquet, Maryline [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium] Uytterhoeven, K. [INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate, Italy ; Instituto de AstrofÃsica de Canarias, Calle via Láctea s/n, 38205 La Laguna, TF, Spain] Morel, Thierry [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE) >] Aerts, C. [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium; Department of Astrophysics, University of Nijmegen, IMAPP, PO Box 9010, 6500 GL Nijmegen, The Netherlands] De Cat, P. [Koninklijke Sterrenwacht van België, Ringlaan 3, 1180 Brussel, Belgium] Mathias, P. [UMR 6525 H. Fizeau, UNS, CNRS, OCA, Campus Valrose, 06108 Nice Cedex 2, France] Lefever, K. [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium; BIRA-IASB, Ringlaan 3, 1180 Brussel, Belgium] Miglio, Andrea [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie >] Poretti, E. [INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate, Italy] Martin-Ruiz, S. [> >] Paparo, M. [> >] Rainer, M. [INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate, Italy] Carrier, F. [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium] Gutierrez-Soto, J. [> >] Valtier, J. C. [UMR 6525 H. Fizeau, UNS, CNRS, OCA, Campus Valrose, 06108 Nice Cedex 2, France] Benko, J. M. [> >] Bognar, Z. [> >] Niemczura, E. [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium; Instytut Astronomiczny Wroclawski, Kopernika 11, 51-622 Wroclaw, Poland] Amado, P. J. [Instituto de AstrofÃsica de AndalucÃa (CSIC), Apdo. 3004, 18080 Granada, Spain] Suarez, J. C. [> >] Moya, A. [Instituto de AstrofÃsica de AndalucÃa (CSIC), Apdo. 3004, 18080 Granada, Spain] Rodriguez-Lopez, C. [> >] Garrido, R. [Instituto de AstrofÃsica de AndalucÃa (CSIC), Apdo. 3004, 18080 Granada, Spain] Publication date : 1-Oct-2009 Journal title : Astronomy and Astrophysics Publisher : EDP Sciences Volume : 506 Pages : 269-280 Audience : International ISSN : 0004-6361 e-ISSN : 1432-0746 City : Les Ulis Country : France Keywords : [en] stars: abundances ; stars: early-type ; stars: oscillations ; stars: individual: HD 180 642Abstract : [en] The known β Cephei star HD 180 642 was observed by the CoRoT satellite in 2007. From the very high-precision light curve, its pulsation frequency spectrum could be derived for the first time (Degroote and collaborators). In this paper, we obtain additional constraints for forthcoming asteroseismic modeling of the target. Our results are based on both extensive ground-based multicolour photometry and high-resolution spectroscopy. We determine T_eff = 24 500± 1000 K and log g = 3.45± 0.15 dex from spectroscopy. The derived chemical abundances are consistent with those for B stars in the solar neighbourhood, except for a mild nitrogen excess. A metallicity Z = 0.0099± 0.0016 is obtained. Three modes are detected in photometry. The degree â is unambiguously identified for two of them: â = 0 and â = 3 for the frequencies 5.48694 d[SUP]-1[/SUP] and 0.30818 d[SUP]-1[/SUP], respectively. The radial mode is non-linear and highly dominant with an amplitude in the U-filter about 15 times larger than the strongest of the other modes. For the third frequency of 7.36673 d[SUP]-1[/SUP] found in photometry, two possibilities remain: â = 0 or 3. In the radial velocities, the dominant radial mode presents a so-called stillstand but no clear evidence of the existence of shocks is observed. Four low-amplitude modes are found in spectroscopy and one of them, with frequency 8.4079 d[SUP]-1[/SUP], is identified as (â ,m)=(3,2). Based on this mode identification, we finally deduce an equatorial rotational velocity of 38± 15 km s[SUP]-1[/SUP]. Based on data gathered with the 1.2m Mercator telescope Roque de los Muchachos, La Palma, the 90cm telescope at Sierra Nevada Observatory, Spain, the 1.5 m telescope at San Pedro Mártir Observatory, Mexico, the 1m RCC and 50 cm telescope at the PiszkéstetÅ Mountain Station of Konkoly Observatory, Hungary, the 2.2 m ESO telescope (ESO Programme 077.D-0311; ESO Large Programme 178.D-0361) at La Silla, Chile, the 1.93 m and 1.52 m telescopes at the Haute-Provence Observatory, France. Current address: Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot; CEA, IRFU, SAp, centre de Saclay, 91191 Gif-sur-Yvette, France.Permalink : http://hdl.handle.net/2268/31640 DOI : 10.1051/0004-6361/200912025 Other URL : http://adsabs.harvard.edu/abs/2009A%26A...506..269B Commentary : http://de.arxiv.org/abs/0906.3626 
[Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium]
