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Asteroseismology of hybrid pulsators made possible: simultaneous MOSTSPACE photometry and ground-based spectroscopy of γ PEG

Handler, G., Matthews, J. M., Eaton, J. A., Daszyńska-Daszkiewicz, J., Kuschnig, R., Lehmann, H., Rodríguez, E., Pamyatnykh, A. A., Zdravkov, T., Lenz, P., and others. (2009) Asteroseismology of hybrid pulsators made possible: simultaneous MOSTSPACE photometry and ground-based spectroscopy of γ PEG. The Astrophysical Journal, 698 (1). L56-L59. ISSN 0004-637X. E-ISSN 1538-4357. (doi:10.1088/0004-637X/698/1/L56)

Abstract

We have acquired simultaneous high-precision space photometry and radial velocities of the bright hybrid β Cep/Slowly Pulsating B pulsator γ Peg. Frequency analyses reveal the presence of six gravity (g) modes of high radial order together with eight low-order β Cep oscillations in both data sets. Mode identification shows that all pulsations have spherical degrees ℓ = 0-2. An 8.5 M ☉ model reproduces the observed pulsation frequencies; all theoretically predicted modes in the β Cep domain are detected. We suggest, contrary to previous authors, that γ Peg is a single star; the claimed orbital variations are due to g-mode pulsation. γ Peg is the first hybrid pulsator for which a sufficiently large number of high-order g modes and low-order pressure (p) and mixed modes have been detected and identified to be usable for in-depth seismic modeling.

Item Type: Article
DOI/Identification number: 10.1088/0004-637X/698/1/L56
Subjects: Q Science > QB Astronomy
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: Agata Makiela
Date Deposited: 14 Mar 2019 10:30 UTC
Last Modified: 03 Jun 2019 09:33 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/72977 (The current URI for this page, for reference purposes)
Rożek, A.: https://orcid.org/0000-0003-2341-2238
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