KIC 10080943: a binary star with two $\gamma$ Doradus/$\delta$ Scuti hybrid pulsators. Analysis of the g modes

TL;DR

This study analyzes four years of Kepler data on the binary star KIC 10080943, revealing both stars as hybrid pulsators with complex g and p mode spectra, and estimating their core rotation periods.

Contribution

It provides the first detailed analysis of the g modes in a binary with two hybrid pulsators, including mode disentanglement and core rotation measurements.

Findings

Both stars are γ Doradus/δ Scuti hybrids.

Core rotation periods are approximately 11 and 7 days.

Identification of rotationally split modes and mode types.

Abstract

We use four years of Kepler photometry to study the non-eclipsing spectroscopic binary KIC 10080943. We find both components to be $\gamma$ Doradus/$\delta$ Scuti hybrids, which pulsate in both p and g modes. We present an analysis of the g modes, which is complicated by the fact that the two sets of $\ell=1$ modes partially overlap in the frequency spectrum. Nevertheless, it is possible to disentangle them by identifying rotationally split doublets from one component and triplets from the other. The identification is helped by the presence of additive combination frequencies in the spectrum that involve the doublets but not the triplets. The rotational splittings of the multiplets imply core rotation periods of about 11 d and 7 d in the two stars. One of the stars also shows evidence of $\ell=2$ modes.