Exploring the empirical instability strip for $\gamma$ Dor-type stars in eclipsing binaries

TL;DR

This study investigates the pulsational properties of $b3$ Dor-type stars in eclipsing binaries, constructing an observational instability strip and analyzing the relationship between pulsation and orbital parameters.

Contribution

It provides the first empirical instability strip for $b3$ Dor stars in eclipsing binaries and explores correlations between pulsation and orbital characteristics.

Findings

Constructed an observational $b3$ Dor instability strip (6850K-7360K).

Identified potential relationships between pulsation periods and orbital parameters.

Most $b3$ Dor stars in the sample are within the instability strip.

Abstract

This research paper has light curve modelling, spectroscopy, and detailed asteroseismic studies for five detached eclipsing binaries with a $\gamma$ Dor component that have been found so far by the sky surveys. The objective is to study the pulsational characteristics of the oscillating stars of the systems, as well as to estimate their absolute parameters and their relation to the pulsational frequencies and enrich the sample size of this kind of system, which has been relatively poor up to today. The physical properties of these systems are compared with other similar cases and the locations of their components are plotted in the Hertzsprung-Russell (HR) diagrams. In order to discover the pulsation frequencies, the photometric data are analysed using eclipsing binary modelling methods and their residuals are subjected to Fourier analysis. Finally, we evaluated that there is a possible relationship between the pulsation periods of the primaries and the orbital period ($P_{\rm orb}$), the force exerted per gram on the surface of the pulsating star ($f$/M$_{\rm puls}$), and the fractional radius of the pulsating star ($r_{\rm puls}$) of the systems, using a sample of 39 eclipsing binary systems with $\gamma$ Dor type primaries. We utilised them to construct a unique observational $\gamma$ Dor instability strip, delineated by a lower limit of 6,850 K at the red edge and an upper limit of 7,360 K at the blue edge on the zero-age main sequence. The majority of 39 pure $\gamma$ Dor stars are located within the region that is covered by this observational strip.