VERY METAL-POOR OUTER-HALO STARS WITH ROUND ORBITS
نویسندگان
چکیده
منابع مشابه
Mining the Galactic Halo for Very Metal-Poor Stars
We study the age and metallicity distribution function (MDF) of metal-poor stars in the Milky Way halo as a function of galactocentric radius by combining N-body simulations and semi-analytical methods. We find that the oldest stars populate the innermost region, while extremely metal-poor stars are more concentrated within r < 60 kpc. We predict that the MDF of [Fe/H]≤ −2 stars varies only ver...
متن کاملModels for extremely metal-poor halo stars
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...
متن کاملThree-dimensional Orbits of Metal-poor Halo Stars and the Formation of the Galaxy
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...
متن کاملSulphur abundance in very metal-poor stars
We have obtained high-resolution high signal-to-noise spectra of the S i nearinfrared doublet at 8694 Å in eight metal-poor stars with metallicities in the range −0.6 ≤[Fe/H]≤ −3.0. Elemental sulphur abundances were derived for six targets and upper limits were set for two of the most metal-poor stars in the sample. The sulphur doublet at 8694.62 Å has been detected in three stars (HD19445, HD2...
متن کاملAbundances in Very Metal-Poor Stars
Metal-poor stars provide information on the characteristics and chemical evolution of the halo population of the Galaxy, the first epoch of star formation and Galaxy formation (not just locally but with relevance to high-redshift objects), and big bang nucleosynthesis. This review looks at recent developments in this subject.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2013
ISSN: 2041-8205,2041-8213
DOI: 10.1088/2041-8205/763/1/l17