Broadening and asymmetry of spectral lines in slowly rotating late A-type stars provide evidence for high-amplitude convective motions. The properties of turbulence observed in the A-star atmospheres are not understood theoretically and contradict results of previous numerical simulations of convection. Here we describe an ongoing effort to understand the puzzling convection signatures of A stars with the help of 3-D hydrodynamic simulations. Our approach combines realistic spectrum synthesis and non-grey hydrodynamic models computed with the CO5BOLD code. We discuss these theoretical predictions and confront them with high-resolution spectra of A stars. Our models have, for the first time, succeeded in reproducing the observed profiles of weak spectral lines without introducing fudge broadening parameters.
@article{arxiv.astro-ph/0610111,
title = {3-D hydrodynamic simulations of convection in A stars},
author = {O. Kochukhov and B. Freytag and N. Piskunov and M. Steffen},
journal= {arXiv preprint arXiv:astro-ph/0610111},
year = {2015}
}
Comments
3 pages, 2 figures; to appear in the proceedings of the IAU Symposium 239, Convection in Astrophysics