Micro- and macroturbulence derived from 3D hydrodynamical stellar atmospheres

TL;DR

This paper explores how 3D hydrodynamical models can predict micro- and macroturbulence in stellar atmospheres, aiding spectroscopic analysis when empirical data is unavailable.

Contribution

It introduces methods to derive micro- and macroturbulence from 3D models and provides initial results for the Sun and Procyon.

Findings

Simulated microturbulence is lower than observed in real stars.

Methods for deriving turbulence parameters from 3D models are discussed.

Preliminary results highlight discrepancies between simulations and observations.

Abstract

The theoretical prediction of micro- and macroturbulence (xi_mic and xi_mac) as a function of stellar parameters can be useful for spectroscopic work based on 1D model atmospheres in cases where an empirical determination of xi_mic is impossible due to a lack of suitable lines and/or macroturbulence and rotational line broadening are difficult to separate. In an effort to exploit the CIFIST 3D model atmosphere grid for deriving the theoretical dependence of xi_mic and xi_mac on effective temperature, gravity, and metallicity, we discuss different methods to derive xi_mic from the numerical simulations, and report first results for the Sun and Procyon. In both cases the preliminary analysis indicates that the microturbulence found in the simulations is significantly lower than in the real stellar atmospheres.