Bibcode
Grigahcène, A.; Uytterhoeven, K.; Antoci, V.; Balona, L.; Catanzaro, G.; Daszyńska-Daszkiewicz, J.; Guzik, J. A.; Handler, G.; Houdek, G.; Kurtz, D. W.; Marconi, M.; Monteiro, M. J. P. F. G.; Moya, A.; Ripepi, V.; Suárez, J.-C.; Borucki, W. J.; Brown, T. M.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Jenkins, J. M.; Kjeldsen, H.; Koch, D.; Bernabei, S.; Bradley, P.; Breger, M.; Di Criscienzo, M.; Dupret, M.-A.; García, R. A.; García Hernández, A.; Jackiewicz, J.; Kaiser, A.; Lehmann, H.; Martín-Ruiz, S.; Mathias, P.; Molenda-Żakowicz, J.; Nemec, J. M.; Nuspl, J.; Paparó, M.; Roth, M.; Szabó, R.; Suran, M. D.; Ventura, R.
Bibliographical reference
Astronomische Nachrichten, Vol.331, Issue 9/10, p.989
Advertised on:
12
2010
Citations
18
Refereed citations
15
Description
Through the observational study of stellar pulsations, the internal
structure of stars can be probed and theoretical models can be tested.
The main sequence γ Doradus (Dor) and δ Scuti (Sct) stars
with masses 1.2-2.5 M&sun; are particularly interesting for
asteroseismic study. The γ Dor stars pulsate in high-order gravity
(g) modes, with pulsational periods of order of one day. The δ Sct
stars, on the other hand, show low-order g and pressure (p) modes with
periods of order of 2 hours. Theory predicts the existence of `hybrid'
stars, i.e. stars pulsating in both types of modes, in an overlap region
between the instability strips of γ Dor and δ Sct stars in
the Hertzsprung-Russell diagram. Hybrid stars are particularly
interesting as the two types of modes probe different regions of the
stellar interior and hence provide complementary model constraints.
Before the advent of Kepler, only a few hybrid stars had been confirmed.
The {{Kepler}} satellite is providing a true revolution in the study of
and search for hybrid stars. Analysis of the first 50 days of {{Kepler}}
data of hundreds of γ Dor and δ Sct candidates reveals
extremely rich frequency spectra, with most stars showing frequencies in
both the δ Sct and γ Dor frequency range. As these results
show that there are practically no pure δ Sct or γ Dor
pulsators, a new observational classification scheme is proposed by
cite{Grig10}. We present their results and characterize 234 stars in
terms of δ Sct, γ Dor, δ Sct/γ Dor or γ
Dor/δ Sct hybrids.