# Damping rates and frequency corrections of Kepler LEGACY stars

## TL;DR

This study estimates damping rates and frequency corrections of radial oscillation modes in Kepler LEGACY stars using a calibrated nonlocal convection model, achieving good agreement with observations across a range of stellar parameters.

## Contribution

It introduces a calibrated nonlocal, time-dependent convection model for stellar oscillation analysis, linking 1D stability calculations with 3D simulation profiles.

## Key findings

- Good agreement with observed damping rates and turbulent pressure profiles.
- Frequency corrections increase with surface temperature and gravity.
- Calibrated model reproduces key features of stellar oscillations.

## Abstract

Linear damping rates and modal frequency corrections of radial oscillation modes in selected LEGACY main-sequence stars are estimated by means of a nonadiabatic stability analysis. The selected stellar sample covers stars observed by Kepler with a large range of surface temperatures and surface gravities. A nonlocal, time-dependent convection model is perturbed to assess stability against pulsation modes. The mixing-length parameter is calibrated to the surface-convection-zone depth of a stellar model obtained from fitting adiabatic frequencies to the LEGACY observations, and two of the nonlocal convection parameters are calibrated to the corresponding LEGACY linewidth measurements. The remaining nonlocal convection parameters in the 1D calculations are calibrated so as to reproduce profiles of turbulent pressure and of the anisotropy of the turbulent velocity field of corresponding 3D hydrodynamical simulations. The atmospheric structure in the 1D stability analysis adopts a temperature-optical-depth relation derived from 3D hydrodynamical simulations. Despite the small number of parameters to adjust, we find good agreement with detailed shapes of both turbulent pressure profiles and anisotropy profiles with depth, and with damping rates as a function of frequency. Furthermore, we find the absolute modal frequency corrections, relative to a standard adiabatic pulsation calculation, to increase with surface temperature and surface gravity.