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. Costa, V., Díaz-Fraile, D., Sota, A., Kwiatkowski, T., Schwarzenberg-Czerny, A., Borczyk, W., Dimitrov, W., Fagas, M., Kamiński, K., Rożek, A., van Wyk, F., Pollard, K. R., Kilmartin, P. M., Weiss, W. W., Guenther, D. B., Moffat, A. F. J., Rucinski, S. M., Sasselov, D. D., and Walker, G. A. H. (hide) (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