Turbulent convection and pulsation stability of stars - II. Theoretical instability strip for $\delta$ Scuti and $\gamma$ Doradus stars

Abstract

By using a non-local and time-dependent convection theory, we have calculated radial and low-degree non-radial oscillations for stellar evolutionary models with $M=1.4$--3.0\,${\mathrm{M}}_{\odot }$. The results of our study predict theoretical instability strips for $\delta$ Scuti and $\gamma$ Doradus stars, which overlap with each other. The strip of $\gamma$ Doradus is slightly redder in colour than that of $\delta$ Scuti. We have paid great attention to the excitation and stabilization mechanisms for these two types of oscillations, and we conclude that radiative $\kappa$ mechanism plays a major role in the excitation of warm $\delta$ Scuti and $\gamma$ Doradus stars, while the coupling between convection and oscillations is responsible for excitation and stabilization in cool stars. Generally speaking, turbulent pressure is an excitation of oscillations, especially in cool $\delta$ Scuti and $\gamma$ Doradus stars and all cool Cepheid- and Mira-like stars. Turbulent thermal convection, on the other hand, is a damping mechanism against oscillations that actually plays the major role in giving rise to the red edge of the instability strip. Our study shows that oscillations of $\delta$ Scuti and $\gamma$ Doradus stars are both due to the combination of $\kappa$ mechanism and the coupling between convection and oscillations, and they belong to the same class of variables at the low-luminosity part of the Cepheid instability strip. Within the $\delta$ Scuti--$\gamma$ Doradus instability strip, most of the pulsating variables are very likely hybrids that are excited in both p and g modes.

16 pages, 20 figures, published 2016 February 19

References in corpus (9)

• Kepler Input Catalog: Photometric Calibration and Stellar Classification
• Revised Stellar Properties of Kepler Targets for the Quarter 1-16 Transit Detection Run
• The Kepler characterization of the variability among A- and F-type stars. I. General overview
• Hybrid gamma Doradus - delta Scuti pulsators: New insights into the physics of the oscillations from Kepler observations
• Results of a Search for gamma Dor and delta Sct Stars with the Kepler Spacecraft
• Galaxy Clustering Evolution in the CNOC2 High-Luminosity Sample
• Turbulent Convection and Pulsational Stability of Variable Stars II. Oscillations of RR Lyrae and Horizontal Branch Red Variable Stars
• A Volume-Limited Photometric Survey of 114 gamma Doradus Candidates
• Turbulent convection and pulsation stability of stars - I. Basic equations for calculations of stellar structure and oscillations

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