Reference : A multisite photometric study of two unusual β Cep stars: the magnetic V2052 Oph and ...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/132491
A multisite photometric study of two unusual β Cep stars: the magnetic V2052 Oph and the massive rapid rotator V986 Oph
English
Handler, G. [Copernicus Astronomical Center, Bartycka 18, 00-716, Warsaw, Poland]
Shobbrook, R. R. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT Australia]
Uytterhoeven, K. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife, Spain,; Departamento de Astrofísica, Universidad de La Laguna (ULL), E-38206 La Laguna, Tenerife, Spain]
Briquet, Maryline mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie >]
Neiner, C. [LESIA, Observatoire de Paris, CNRS UMR 8109, UPMC, Université Paris Diderot, 5 place Jules Janssen, 92190, Meudon, France]
Tshenye, T. [Department of Physics, University of the North-West, Private Bag X2046, Mmabatho, 2735, South Africa]
Ngwato, B. [Department of Physics, University of the North-West, Private Bag X2046, Mmabatho, 2735, South Africa]
van Winckel, H. [Instituut voor Sterrenkunde, K. U. Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium]
Guggenberger, E. [Institut für Astronomie, Universität Wien, Türkenschanzstrasse 17, A-1180, Wien, Austria]
Raskin, G. [Instituut voor Sterrenkunde, K. U. Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium]
Rodríguez, E. [Instituto de Astrofisica de Andalucia, C.S.I.C., Apartado 3004, 18080, Granada, Spain]
Mazumdar, A. [Homi Bhabha Centre for Science Education (TIFR), V. N. Purav Marg, Mumbai, 400088, India]
Barban, C. [LESIA, Observatoire de Paris, CNRS UMR 8109, UPMC, Université Paris Diderot, 5 place Jules Janssen, 92190, Meudon, France]
Lorenz, D. [Institut für Astronomie, Universität Wien, Türkenschanzstrasse 17, A-1180, Wien, Austria]
Vandenbussche, B. [Instituut voor Sterrenkunde, K. U. Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium]
Şahin, T. [Faculty of Science, Space Science and Technologies Department, Akdeniz University, 07058, Antalya, Turkey,; TUBITAK National Observatory, Akdeniz University Campus, 07058, Antalya, Turkey]
Medupe, R. [Department of Physics, University of the North-West, Private Bag X2046, Mmabatho, 2735, South Africa]
Aerts, C. [Instituut voor Sterrenkunde, K. U. Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium)]
1-Aug-2012
Monthly Notices of the Royal Astronomical Society
Blackwell Publishing
424
2380-2391
Yes (verified by ORBi)
0035-8711
Oxford
United Kingdom
[en] stars: early-type ; stars: individual: V2052 Oph ; stars: individual: V986 Oph ; stars: magnetic field ; stars: oscillations ; stars: rotation
[en] We report a multisite photometric campaign for the β Cep stars V2052 Oph and V986 Oph. 670 h of high-quality differential photoelectric Strömgren, Johnson and Geneva time-series photometry was obtained with eight telescopes on five continents during 182 nights. Frequency analyses of the V2052 Oph data enabled the detection of three pulsation frequencies, the first harmonic of the strongest signal, and the rotation frequency with its first harmonic. Pulsational mode identification from analysing the colour amplitude ratios confirms the dominant mode as being radial, whereas the other two oscillations are most likely l = 4. Combining seismic constraints on the inclination of the rotation axis with published magnetic field analyses we conclude that the radial mode must be the fundamental mode. The rotational light modulation is in phase with published spectroscopic variability, and consistent with an oblique rotator for which both magnetic poles pass through the line of sight. The inclination of the rotation axis is 54° < i < 58° and the magnetic obliquity 58° < β < 66°. The possibility that V2052 Oph has a magnetically confined wind is discussed. The photometric amplitudes of the single oscillation of V986 Oph are most consistent with an l = 3 mode, but this identification is uncertain. Additional intrinsic, apparently temporally incoherent light variations of V986 Oph are reported. Different interpretations thereof cannot be distinguished at this point, but this kind of variability appears to be present in many OB stars. The prospects of obtaining asteroseismic information for more rapidly rotating β Cep stars, which appear to prefer modes of higher l, are briefly discussed.
http://hdl.handle.net/2268/132491
10.1111/j.1365-2966.2012.21414.x
http://adsabs.harvard.edu/abs/2012MNRAS.424.2380H
http://de.arxiv.org/abs/1205.6401

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