• DOI:10.1088/2041-8205/713/2/L192
• Corpus ID: 56144432

HYBRID γ DORADUS-δ SCUTI PULSATORS: NEW INSIGHTS INTO THE PHYSICS OF THE OSCILLATIONS FROM KEPLER OBSERVATIONS

@article{Grigahcne2010HYBRIDD,
  title={HYBRID $\gamma$ DORADUS-$\delta$ SCUTI PULSATORS: NEW INSIGHTS INTO THE PHYSICS OF THE OSCILLATIONS FROM KEPLER OBSERVATIONS},
  author={Ahmed Grigahc{\`e}ne and Victoria Antoci and Luis A. Balona and G. Catanzaro and Jadwiga Daszyńska-Daszkiewicz and Joyce A. Guzik and Gerald Handler and G Houdek and Donald W. Kurtz and Marcella Marconi and M{\'a}rio J. P. F. G. Monteiro and Andr{\'e}s Moya and Vincenzo Ripepi and J. C. Su{\'a}rez and Katrien Uytterhoeven and William J. Borucki and Timothy M. Brown and J{\o}rgen Christensen-Dalsgaard and Ronald L. Gilliland and Jon M. Jenkins and Hans Kjeldsen and David G. Koch and Stefano Bernabei and Paul Andrew Bradley and Michel Breger and Marcella Di Criscienzo and M-A. Dupret and R. A. Garc{\'i}a and A. Garc{\'i}a Hern{\'a}ndez and Jason Jackiewicz and Andreas M. Kaiser and Holger Lehmann and S. Marin-Ruiz and Ph. Mathias and Joanna Molenda–Żakowicz and J. M. Nemec and Janos Nuspl and Margit Papar{\'o} and Markus Roth and R{\'o}bert Szab{\'o} and Marian Doru Suran and Rita Ventura},
  journal={The Astrophysical Journal},
  year={2010},
  volume={713}
}

• A. Grigahcène, V. Antoci, +39 authors R. Ventura
• Published 5 January 2010
• Physics
• The Astrophysical Journal

Observations of the pulsations of stars can be used to infer their interior structure and test theoretical models. The main-sequence γ Doradus (Dor) and δ Scuti (Sct) stars with masses 1.2-2.5 M ☉ are particularly useful for these studies. The γ Dor stars pulsate in high-order g-modes with periods of order 1 day, driven by convective blocking at the base of their envelope convection zone. The δ Sct stars pulsate in low-order g- and p-modes with periods of order 2 hr, driven by the κ mechanism operating in the He II ionization zone. Theory predicts an overlap region in the Hertzsprung-Russell diagram between instability regions, where hybrid stars pulsating in both types of modes should exist. The two types of modes with properties governed by different portions of the stellar interior provide complementary model constraints. Among the known γ Dor and δ Sct stars, only four have been confirmed as hybrids. Now, analysis of combined Quarter 0 and Quarter 1 Kepler data for hundreds of variable stars shows that the frequency spectra are so rich that there are practically no pure δ Sct or γ Dor pulsators, i.e., essentially all of the stars show frequencies in both the δ Sct and the γ Dor frequency range. A new observational classification scheme is proposed that takes into account the amplitude as well as the frequency and is applied to categorize 234 stars as δ Sct, γ Dor, δ Sct/γ Dor or γ Dor/δ Sct hybrids.