Asteroseismic Modeling of 1,153 Kepler Red Giant Branch Stars: Improved Stellar Parameters with Gravity-Mode Period Spacings and Luminosity Constraints

TL;DR

This study improves stellar parameter estimates for 1,153 Kepler red giant stars by incorporating gravity-mode period spacings and luminosity constraints, significantly enhancing the precision of fundamental stellar properties.

Contribution

It introduces asteroseismic modeling that combines multiple observational constraints, leading to the most precise characterization of red giant stars to date.

Findings

Uncertainties reduced to 2.9% in mass and 11% in age.

Recalibrated seismic scaling relations for red giants.

Confirmed surface term dependence on gravity and temperature.

Abstract

This paper reports estimated stellar parameters of 1,153 Kepler red giant branch stars determined with asteroseismic modeling. We use radial-mode oscillation frequencies, gravity-mode period spacings, Gaia luminosities, and spectroscopic data to characterize these stars. Compared with previous studies, we find that the two additional observed constraints, i.e., the gravity-mode period spacing and luminosity, significantly improve the precision of fundamental stellar parameters. The typical uncertainties are 2.9% for the mass, 11% for the age, 1.0% for the radius, 0.0039 dex for the surface gravity, and 0.5\% for the helium core mass, making this the best-characterized large sample of red-giant stars available to date. With better characterizations for these red giants, we recalibrate the seismic scaling relations and study the surface term on the red-giant branch. We confirm that the surface term depends on the surface gravity and effective temperature, but there is no significant correlation with metallicity.