Asteroseismology of hybrid pulsators made possible: simultaneous MOST space photometry and ground-based spectroscopy of Gamma Peg
| Autor: | G. Handler, J. M. Matthews, J. A. Eaton, J. Daszyńska-Daszkiewicz, R. Kuschnig, H. Lehmann, E. Rodríguez, A. A. Pamyatnykh, T. Zdravkov, P. Lenz, V. Costa, D. Díaz-Fraile, A. Sota, T. Kwiatkowski, A. Schwarzenberg-Czerny, W. Borczyk, W. Dimitrov, M. Fagas, K. Kamiński, A. Rożek, F. van Wyk, K. R. Pollard, P. M. Kilmartin, W. W. Weiss, D. B. Guenther, A. F. J. Moffat, S. M. Rucinski, D. D. Sasselov, G. A. H. Walker |
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| Rok vydání: | 2009 |
| Předmět: |
Physics
Solar mass 010504 meteorology & atmospheric sciences Astrophysics::High Energy Astrophysical Phenomena FOS: Physical sciences Astronomy and Astrophysics Astrophysics 01 natural sciences Asteroseismology Single star Photometry (optics) Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Seismic modeling 0103 physical sciences PEG ratio Astrophysics::Solar and Stellar Astrophysics Spectroscopy 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences QB |
| ISSN: | 0004-637X |
| DOI: | 10.48550/arxiv.0905.1193 |
| Popis: | We have acquired simultaneous high-precision space photometry and radial velocities of the bright hybrid Beta Cep/SPB pulsator Gamma Peg. Frequency analyses reveal the presence of six g modes of high radial order together with eight low-order Beta Cep oscillations in both data sets. Mode identification shows that all pulsations have spherical degrees l = 0 - 2. An 8.5 solar mass model reproduces the observed pulsation frequencies; all theoretically predicted modes are detected. We suggest, contrary to previous authors, that Gamma Peg is a single star; the claimed orbital variations are due to g-mode pulsation. Gamma Peg is the first hybrid pulsator for which a sufficiently large number of high-order g modes and low order p and mixed modes have been detected and identified to be usable for in-depth seismic modeling. Comment: 18 pages (4 pages in journal style), 4 figures, accepted for ApJ Letters |
| Databáze: | OpenAIRE |
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