An asteroseismic study of the β Cephei star 12 Lacertae: multisite spectroscopic observations, mode identification and seismic modelling |
| |
| Authors: | M. Desmet,M. Briquet &dagger ,A. Thoul &Dagger ,W. Zima,P. De Cat,G. Handler,I. Ilyin,E. Kambe,J. Krzesinski,H. Lehmann,S. Masuda,P. Mathias,D. E. Mkrtichian,J. Telting,K. Uytterhoeven,S. L. S. Yang, C. Aerts |
| |
| Affiliation: | Institute of Astronomy –KULeuven, Celestijnenlaan 200D, 3001 Leuven, Belgium;Institut d'Astrophysique et de Géophysique de l'Universitéde Liège, 17 Allée du 6 Août, 4000 Liège, Belgium;Koninklijke Sterrenwacht van België, Ringlaan 3, 1180 Brussel, Belgium;Institut für Astronomie, Universistät Wien, Türkenschanzstrasse 17, 1180 Wien, Austria;Astrophysical Institute Potsdam, An der Sternwarte 16, D-14482 Potsdam, Germany;Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama 719-0232, Japan;Mt. Suhora Observatory, Cracow Pedagogical University, Ul. Podchorazych 2, 30-084 Cracow, Poland;Karl-Schwarzschild-Observatorium, Thüringer Landessternwarte, 7778 Tautenburg, Germany;Tokushima Science Museum, Asutamu Land Tokushima, 45-22 Kibigadani, Nato, Itano-cho, Itano-gun, Tokushima 779-0111, Japan;UNS, CNRS, OCA, Campus Valrose, UMR 6525 H. Fizeau, F-06108 Nice Cedex 2, France;Astronomical Observatory of Odessa National University, Marazlievskaya, 1v, 65014 Odessa, Ukraine;Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Spain;Instituto de Astrofísica de Canarias, Calle Via Láctea s/n, 38205 La Laguna, TF, Spain;Department of Physics and Astronomy, Universtity of Victoria, Victoria, BC V8W 3P6, Canada;Department of Astrophysics, University of Nijmegen, PO Box 9010, 6500 GL Nijmegen, the Netherlands |
| |
| Abstract: | We present the results of a spectroscopic multisite campaign for the β Cephei star 12 (DD) Lacertae. Our study is based on more than thousand high-resolution high S/N spectra gathered with eight different telescopes in a time span of 11 months. In addition, we make use of numerous archival spectroscopic measurements. We confirm 10 independent frequencies recently discovered from photometry, as well as harmonics and combination frequencies. In particular, the slowly pulsating B-stars (SPB)-like g -mode with frequency 0.3428 d−1 reported before is detected in our spectroscopy. We identify the four main modes as (ℓ1, m 1) = (1, 1), (ℓ2, m 2) = (0, 0), (ℓ3, m 3) = (1, 0) and (ℓ4, m 4) = (2, 1) for f 1= 5.178 964 d−1, f 2= 5.334 224 d−1, f 3= 5.066 316 d−1 and f 4= 5.490 133 d−1 , respectively. Our seismic modelling shows that f 2 is likely the radial first overtone and that the core overshooting parameter αov is lower than 0.4 local pressure scale heights. |
| |
| Keywords: | stars: individual: 12 Lac stars: interiors stars: oscillations |
|
|
