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3-D hydrodynamic simulations of convection in A stars

Published online by Cambridge University Press:  01 August 2006

O. Kochukhov
Affiliation:
Astronomical Observatory, Uppsala University, Box 515, 751 20, Uppsala, Sweden
B. Freytag
Affiliation:
Astronomical Observatory, Uppsala University, Box 515, 751 20, Uppsala, Sweden
N. Piskunov
Affiliation:
Astronomical Observatory, Uppsala University, Box 515, 751 20, Uppsala, Sweden
M. Steffen
Affiliation:
Astrophysikalisches Institut Potsdam, an der Sternwarte 16, 14482 Potsdam, Germany
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Abstract

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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.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2007

References

Freytag, B., Steffen, M., Wedemeyer, S., & Ludwig, H.-G. 2004, cob User Manual, http://www.astro.uu.se/~bf/co5bold_main.htmlGoogle Scholar
Freytag, B. & Steffen, M. 2004, in The A-Star Puzzle, eds. Zverko, J., Žižňovský, J., Adelman, S.J., Weiss, W.W., IUAS 224, 139Google Scholar
Kochukhov, O. & Ryabchikova, T. 2001, A&A 374, 615Google Scholar
Landstreet, J.D. 1998, A&A 338, 1041Google Scholar
Piskunov, N. 1992, in Stellar Magnetism, eds. Glagolevskij, Yu.V., Romanyuk, I.I., St. Petersburg, 92Google Scholar
Wedemeyer, S., Freytag, B., Steffen, M., Ludwig, H.-G., & Holweger, H. 2004, A&A 414, 1121Google Scholar