Interpolation of spectra from 3D model atmospheres

TL;DR

This paper introduces a new interpolation tool for 3D stellar atmosphere spectra using radial basis functions, enabling easier integration of 3D models into spectral analysis workflows.

Contribution

The authors developed and released a code that interpolates spectra from 3D hydrodynamical models, making 3D stellar atmosphere data more accessible for analysis.

Findings

Provides accurate interpolated spectra with error estimates.

Enables routine use of 3D models in spectral analysis.

Includes graphical tools for error visualization.

Abstract

The use of 3D hydrodynamical simulations of stellar surface convection for model atmospheres is computationally expensive. Although these models have been available for quite some time, their use is limited because of the lack of extensive grids of simulations and associated spectra. Our goal is to provide a method to interpolate spectra that can be applied to both 1D and 3D models, and implement it in a code available to the community. This tool will enable the routine use of 3D model atmospheres in the analysis of stellar spectra.} We have developed a code that makes use of radial basis functions to interpolate the spectra included in the CIFIST grid of 84 three-dimensional model atmospheres. Spectral synthesis on the hydrodynamical simulations was previously performed with the code ASS$\epsilon$T. We make a tool for the interpolation of 3D spectra available to the community. The code provides interpolated spectra and interpolation errors for a given wavelength interval, and a combination of effective temperature, surface gravity, and metallicity. In addition, it optionally provides graphical representations of the RMS and mean ratio between 1D and 3D spectra, and maps of the errors in the interpolated spectra across the parameter space.