stars: oscillations; stars: rotation; stars: variables: general
Abstract :
[en] γ Doradus stars pulsate with high-order gravity modes having typical frequencies which can be comparable to or higher than their rotation frequencies. Therefore, rotation has a non-negligible effect on their oscillation properties. To explore the rotation-pulsation coupling in γ Dor stars, we perform a non-adiabatic study including the traditional approximation of rotation on a grid of spherical stellar models covering the mass range 1.4 < M[SUB]*[/SUB] < 2.1 M[SUB]&sun;[/SUB]. This approximation allows us to treat the effect of the Coriolis force on the frequencies and the stability of high-order g modes. The effect of the Coriolis force depends on the kind of mode considered (prograde sectoral or not) and increases with their periods. As a consequence, we first find that the period spacing between modes is no longer periodically oscillating around a constant value. Secondly, we show that the frequency gap (5-15 cycles day[SUP]-1[/SUP]) arising from stable modes between γ Dor-type high-order g modes and δ Scuti-type modes can be easily filled by g-mode frequencies shifted to higher values by the rotation. Thirdly, we analyse the combined effect of diffusive mixing and the Coriolis force on the period spacings. And finally, we predict a slight broadening of the γ Dor instability strip.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Bouabid, M.-P.; Laboratoire Lagrange, UMR7293, Université de Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d'Azur, F-06300 Nice, France ; Institut d'Astrophysique et de Géophysique de l'Université de Liège, Allée du 6 Août, B-17 4000 Liège, Belgium
Dupret, Marc-Antoine ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Salmon, Sébastien ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Montalban Iglesias, Josefa ; Institut d'Astrophysique et de Géophysique de l'Université de Liège, Allée du 6 Août, B-17 4000 Liège, Belgium
Miglio, A.; School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT
Noels-Grötsch, Arlette ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Language :
English
Title :
Effects of the Coriolis force on high-order g modes in γ Doradus stars
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