First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
- R. Cayrel, É. Depagne, B. Nordstrom
- Physics
- 4 November 2003
In the framework of the ESO Large Programme "First Stars", very high-quality spectra of some 70 very metal-poor dwarfs and giants were obtained with the ESO VLT and UVES spectrograph. These stars are…
Stellar Chemical Signatures and Hierarchical Galaxy Formation
- K. Venn, M. Irwin, M. Shetrone, C. Tout, V. Hill, E. Tolstoy
- Physics
- 4 June 2004
To compare the chemistries of stars in the Milky Way dwarf spheroidal (dSph) satellite galaxies with stars in the Galaxy, we have compiled a large sample of Galactic stellar abundances from the…
Star-Formation Histories, Abundances, and Kinematics of Dwarf Galaxies in the Local Group
- E. Tolstoy, V. Hill, M. Tosi
- Physics
- 29 April 2009
Within the Local Universe galaxies can be studied in great detail star by star, and here we review the results of quantitative studies in nearby dwarf galaxies. The color-magnitude diagram synthesis…
An extremely primitive star in the Galactic halo
- E. Caffau, P. Bonifacio, V. Hill
- PhysicsNature
- 1 September 2011
It is shown that low-mass stars can be formed at very low metallicity, that is, below the critical value of Z, which implies that the stellar material must have experienced temperatures above two million kelvin in its history, given that this is necessary to destroy lithium.
VLT/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies. I. Nucleosynthesis and Abundance Ratios
- M. Shetrone, K. Venn, E. Tolstoy, F. Primas, V. Hill, A. Kaufer
- Physics
- 8 November 2002
We have used the Ultraviolet Echelle Spectrograph (UVES) on Kueyen (UT2) of the Very Large Telescope to take spectra of 15 individual red giants in the Sculptor, Fornax, Carina, and Leo I dwarf…
The metal content of bulge field stars from FLAMES-GIRAFFE spectra - I. Stellar parameters and iron abundances
- M. Zoccali, V. Hill, S. Ortolani
- Physics
- 8 May 2008
Aims. We determine the iron distribution function (IDF) for bulge field stars, in three different fields along the Galactic minor axis and at latitudes b = −4 ◦ , b = −6 ◦ ,a ndb = −12 ◦ . A fourth…
First stars. I. The extreme r-element rich, iron-poor halo giant CS 31082-001 - Implications for the r-process site(s) and radioactive cosmochronology
We present a high-resolution (R = 75 000, S/N 500) spectroscopic analysis of the bright (V = 11.7), extreme halo giant CS 31082-001 ((Fe/H) = 2.9), obtained in an ESO-VLT Large Programme dedicated to…
The Hamburg/ESO R-process enhanced star survey (HERES). II. Spectroscopic analysis of the survey sample
- P. Barklem, N. Christlieb, D. Reimers
- Physics
- 3 May 2005
We present the results of analysis of "snapshot" spectra of 253 metal-poor halo stars −3.8 ≤ (Fe/H) ≤− 1.5 obtained in the HERES survey. The snapshot spectra have been obtained with VLT/UVES and have…
First stars VI - Abundances of C, N, O, Li, and mixing in extremely metal-poor giants. Galactic evolution of the light elements
We have investigated the poorly-understood origin of nitrogen in the early Galaxy by determining N abundances from the NH band at 336 nm in 35 extremely metal-poor halo giants, with carbon and oxygen…
Measurement of stellar age from uranium decay
The observation of this cosmochronometer gives the most direct age determination of the Galaxy, and with improved theoretical and laboratory data, it will provide a highly precise lower limit to the age of the Universe.
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