Sökning: WFRF:(Hauschildt Peter)
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Radiation-hydrodyna...
Radiation-hydrodynamics Simulations of Surface Convection in a Late M-dwarf
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- Ludwig, Hans-Günter (författare)
- Lund University,Lunds universitet,Astronomi - Genomgår omorganisation,Institutionen för astronomi och teoretisk fysik - Genomgår omorganisation,Naturvetenskapliga fakulteten,Lund Observatory - Undergoing reorganization,Department of Astronomy and Theoretical Physics - Undergoing reorganization,Faculty of Science
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Hauschildt, Peter (författare)
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(creator_code:org_t)
- 2001
- 2001
- Engelska.
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Ingår i: Astronomische Gesellschaft Abstract Series, Vol. 18. Abstracts of Contributed Talks and Posters presented at the Annual Scientific Meeting of the Astronomische Gesellschaft at the Joint European and National Meeting JENAM 2001 of the European Astronomical. ; 18
- Relaterad länk:
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https://lup.lub.lu.s...
Abstract
Ämnesord
Stäng
- Based on detailed 2D and 3D numerical radiation hydrodynamicscalculations of time-dependent compressible convection, we have studiedthe dynamics and thermal structure of the convective surface layers of aprototypical late-type M-dwarf at Teff=2800 K, and log g=5.0with solar chemical composition. The thermal structure of the atmosphereis dominated by molecular absorption, the formation of dust grains isnot important for the chosen model parameters. In the multi dimensionalmodels the radiative transfer is treated by a multi-group (4 groups)approach which provides a simplified, nevertheless rather realistictreatment of the complex radiative energy transport. The equation ofstate includes the important contribution of H2 moleculeformation. Our models predict a convective pattern at the surface of anlate M-dwarf qualitatively similar to solar granulation. Quantitatively,the convective turn-over timescale amounts to ≈ 100 s, a typicalhorizontal scale of convective cells to 80 km, and a relative intensitycontrast of the granular pattern to 1.1 %. The efficiency of convectiveenergy transport corresponds to an effective mixing-length parameterbetween 1.5 to 2.1 depending on the thermal property which isrepresented. The models provide mixing timescales due to atmosphericovershoot which can be extrapolated to lower effective temperatureswhere dust grains are present and mixed into optically thin layers.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
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