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3-D hydrodynamic simulations of convection in A stars

O. Kochukhov·B. Freytag·N. Piskunov·M. Steffen
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Abstract

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.

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O. Kochukhov, B. Freytag, N. Piskunov, M. Steffen. 2006-10-04. 3-D hydrodynamic simulations of convection in A stars. https://doi.org/10.1017/s1743921307000130

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