KIC 10080943: An eccentric binary system containing two pressure- and gravity-mode hybrid pulsators

TL;DR

This study analyzes an eccentric binary system containing two hybrid pulsators using four years of Kepler photometry and spectroscopy, providing insights into stellar structure, evolution, and rotation rates of intermediate-mass stars.

Contribution

It presents the first detailed observational constraints on an eccentric binary with hybrid pulsators, combining spectral disentangling, light curve modeling, and pulsation analysis.

Findings

Identified two hybrid pulsators with specific masses and radii.

Detected rotational splitting in pulsation modes for both stars.

Estimated core-to-surface rotation rates for the components.

Abstract

Gamma Doradus and delta Scuti pulsators cover the transition region between low mass and massive main-sequence stars, and as such, are critical for testing stellar models. When they reside in binary systems, we can combine two independent methods to derive critical information, such as precise fundamental parameters to aid asteroseismic modelling. In the Kepler light curve of KIC10080943, clear signatures of gravity- and pressure-mode pulsations have been found. Ground-based spectroscopy revealed this target to be a double-lined binary system. We present the analysis of four years of Kepler photometry and high-resolution spectroscopy to derive observational constraints with which to evaluate theoretical predictions of the stellar structure and evolution for intermediate-mass stars. We used the method of spectral disentangling to determine atmospheric parameters for both components and derive the orbital elements. With PHOEBE, we modelled the ellipsoidal variation and reflection signal of the binary in the light curve and used classical Fourier techniques to analyse the pulsation modes. We show that the eccentric binary system KIC10080943 contains two hybrid pulsators with masses $M_1=2.0\pm0.1~M_\odot$ and $M_2=1.9\pm0.1~M_\odot$, with radii $R_1=2.9\pm0.1~R_\odot$ and $R_2=2.1\pm0.2~R_\odot$. We detect rotational splitting in the g modes and p modes for both stars and use them to determine a first rough estimate of the core-to-surface rotation rates for the two components, which will be improved by future detailed seismic modelling.