M3DIS -- A grid of 3D radiation-hydrodynamics stellar atmosphere models for stellar surveys

TL;DR

This paper introduces M3DIS, a new efficient framework for generating 3D radiation-hydrodynamics stellar atmosphere models and synthetic spectra, facilitating large-scale stellar surveys and improving accuracy in stellar parameter analysis.

Contribution

We developed a self-consistent, high-performance approach to produce 3D RHD models and spectra for FGK stars, overcoming previous computational bottlenecks.

Findings

Validated the solar model against observations.

Achieved rapid computation of 3D RHD models within a few thousand CPU hours.

Enabled generation of multi-dimensional synthetic stellar spectra.

Abstract

Large-scale stellar surveys, such as SDSS-V, 4MOST, WEAVE, and PLATO, require accurate atmospheric models and synthetic spectra of stars for accurate analyses of fundamental stellar parameters and chemical abundances. The primary goal of our work is to develop a new approach to solve radiation-hydrodynamics (RHD) and generate model stellar spectra in a self-consistent and highly efficient framework. We build upon the Copenhagen legacy RHD code, the MULTI3D non-local thermodynamic equilibrium (NLTE) code, and the DISPATCH high-performance framework. The new approach allows us to calculate 3D RHD models of stellar atmospheres on timescales of a few thousand CPU hours and to perform subsequent spectrum synthesis in local thermodynamic equilibrium (LTE) or NLTE for the desired physical conditions within the parameter space of FGK-type stars. We compare the 3D RHD solar model with other available models and validate its performance against solar observations, including the centre-to-limb variation of intensities and key solar diagnostic lines of H and Fe. We show that the performance of the new code allows to overcome the main bottleneck in 3D NLTE spectroscopy and enables calculations of multi-dimensional grids of synthetic stellar observables for comparison with modern astronomical observations.