Three-dimensional models of metal-poor stars
نویسندگان
چکیده
منابع مشابه
Three-dimensional models of metal-poor stars
I present here the main results of recent realistic, 3D, hydrodynamical simulations of convection at the surface of metal-poor red giant stars. I discuss the application of these convection simulations as time-dependent, 3D, hydrodynamical model atmospheres to spectral line formation calculations and abundance analyses. The impact of 3D models on derived elemental abundances is investigated by ...
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Two alternative scenarios concerning the origin and evolution of extremely metal-poor halo stars are investigated. The first one assumes that the stars have been completely metal-free initially and produced observed carbon and nitrogen overabundances during the peculiar core helium flash typical for low-mass Population III stars. The second scenario assumes that the initial composition resulted...
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We present the three-dimensional orbital motions of metal-poor stars in conjunction with their metal abundances, for the purpose of getting insight into the formation process of the Galaxy. Our sample stars, which include metal-deficient red giants and RR Lyrae variables observed by the Hipparcos satellite, are least affected by known systematics, stemmed from kinematic bias, metallicity calibr...
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Previous calculations of the statistical equilibrium of aluminium in the solar photosphere have shown that NLTE populations hardly affect Al line formation in the Sun; however, in metal-poor stars the influence of electron collisions is reduced, and a UV radiation field enhanced due to smaller background line opacity results in more pronounced NLTE effects. Thus analyses based onNLTEpopulations...
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ژورنال
عنوان ژورنال: Physica Scripta
سال: 2008
ISSN: 0031-8949,1402-4896
DOI: 10.1088/0031-8949/2008/t133/014004