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First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
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
An extremely primitive star in the Galactic halo
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.
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
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.
The metal-poor end of the Spite plateau - I. Stellar parameters, metallicities, and lithium abundances
Context. The primordial nature of the Spite plateau is at odds with the WMAP satellite measurements, implying a primordial Li production at least three times higher than observed. It has also been
First stars VIII. Enrichment of the neutron-capture elements in the early Galaxy
Context: Extremely metal-poor (EMP) stars in the halo of the Galaxy are sensitive probes of the production of the first heavy elements and the efficiency of mixing in the early interstellar medium.
TOPoS - II. On the bimodality of carbon abundance in CEMP stars Implications on the early chemical evolution of galaxies
Context. In the course of the TOPoS (Turn Off Primordial Stars) survey, aimed at discovering the lowest metallicity stars, we have found several carbon-enhanced metal-poor (CEMP) stars. These stars
A high-resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy
For the first time we show the detailed, late-stage, chemical evolution history of a small nearby dwarf spheroidal galaxy in the Local Group. We present the results of a high-resolution (R ~ 20 000,
Chemical abundances in LMC stellar populations - I. The inner disk sample
We have used FLAMES (the Fibre Large Array Multi Element Spectrograph) at the VLT-UT2 telescope to obtain spectra of a large sample of red giant stars from the inner disk of the LMC, ~2 kpc from the