A Theoretical γ Doradus Instability Strip

Abstract

In this paper, we present the first theoretical γ Doradus instability strip. We find that our model instability strip agrees very well with the previously established, observationally based, instability strip of Handler & Shobbrook. We stress, as do Guzik et al., that the convection zone depth plays the major role in the determination of our instability strip. Once this depth becomes too deep or too shallow, the convection zone no longer allows for pulsational instability. Our theoretical γ Dor instability strip is bounded by ∼6850 and 7360 K at the red and blue edge, respectively, on the zero-age main sequence and by ∼6560 and 7000 K at the red and blue edge, respectively, approximately 2 mag more luminous. This theoretical strip, transformed to the observer's color-magnitude diagram, overlays the region where most of the 30 bona fide γ Dor stars are found.