# Mending the structural surface effect of 1D stellar structure models with non-solar metallicities based on interpolated 3D envelopes

## TL;DR

This paper introduces an interpolation method for 3D stellar envelope data to improve 1D stellar models, reducing systematic errors in asteroseismic frequency predictions, especially for stars with non-solar metallicities.

## Contribution

The authors develop a novel interpolation scheme for 3D stellar envelopes as a function of key parameters, enhancing the accuracy of 1D models for asteroseismology.

## Key findings

- Interpolation accurately reproduces stellar envelope structures.
- Frequency shifts depend on stellar evolution stage.
- Neglecting modal effects causes systematic errors.

## Abstract

1D stellar evolution codes employ rudimentary treatments of turbulent convection. For stars with convective envelopes, this leads to systematic errors in the predicted oscillation frequencies needed for asteroseismology. One way of mending these structural inadequacies is through patching, whereby the outermost layers of 1D models are replaced by the mean stratifications from 3D simulations. In order to viably implement this approach in asteroseismic analysis, interpolation throughout precomputed 3D envelopes is required. We present a method that interpolates throughout precomputed 3D envelopes as a function of effective temperature, surface gravity, and metallicity. We conduct a series of validation tests that demonstrate that the scheme reliably and accurately reproduces the structures of stellar envelopes and apply our method to the Sun as well as two stars observed by Kepler. We parameterize the frequency shift that results from patching and show that the functional forms are evolutionary dependent. In addition we find that neglecting modal effects, such as non-adiabatic energetics, introduces systematic errors in asteroseimically obtained stellar parameters. Both these results suggest that a cautious approach is necessary when utilizing empirical surface corrections in lieu of patching models. Our results have important implications, particularly for characterizing exoplanet systems, where accuracy is of utmost concern.