Explanipedia

TOPoS V: Abundance ratios in a sample of very metal-poor turn-off stars Open

P. François, E. Caffau, P. Bonifacio, M. Spite, F. Spite , et al. · 2018

Extremely metal-poor stars are keys to understand the early evolution of our Galaxy. The ESO large programme TOPoS has been tailored to analyse a new set of metal-poor turn-off stars, whereas most of the previously known extremely metal-po…

TOPoS Open

P. François, E. Caffau, P. Bonifacio, M. Spite, F. Spite , et al. · 2018

Context. Extremely metal-poor stars are keys to understand the early evolution of our Galaxy. The ESO large programme TOPoS has been tailored to analyse a new set of metal-poor turn-off stars, whereas most of the previously known extremely…

Using the CIFIST grid of CO<sup>5</sup>BOLD3D model atmospheres to study the effects of stellar granulation on photometric colours Open

P. Bonifacio, E. Caffau, H.‐G. Ludwig, M. Steffen, Francesco Castelli , et al. · 2017

Context. The atmospheres of cool stars are temporally and spatially inhomogeneous due to the effects of convection. The influence of this inhomogeneity, referred to as granulation, on colours has never been investigated over a large range …

Using the CIFIST grid of CO5BOLD 3D model atmospheres to study the effects of stellar granulation on photometric colours. I. Grids of 3D corrections in the UBVRI, 2MASS, Hipparcos, Gaia, and SDSS systems Open

P. Bonifacio, E. Caffau, H.‐G. Ludwig, M. Steffen, Francesco Castelli , et al. · 2017

The atmospheres of cool stars are temporally and spatially inhomogeneous due to the effects of convection.The influence of this inhomogeneity, referred to as granulation, on colours has never been investigated over a large range of effecti…

TOPoS: III. An ultra iron-poor CEMP multiple system Open

E. Caffau, P. Bonifacio, M. Spite, F. Spite, L. Monaco , et al. · 2016

Aims. One of the primary objectives of the TOPoS survey is to search for the most metal-poor stars. Our search has led to the discovery of one of the most iron-poor objects known, SDSS J092912.32+023817.0. This object is a multiple system,…

First Stars XVI. HST/STIS Abundances Of Heavy Elements In The Uranium-Rich Metal-Poor Star CS 31082-001 Open

Curtis J. Mello, M. Spite, B. Barbuy, F. Spite, E. Caffau , et al. · 2016

Context. The origin and site(s) of the r-process nucleosynthesis is(are) still not known with certainty, but complete, detailed r-element abundances off er our best clues. The few extremely metal-poor (EMP) stars with large r-element exces…

HST/STIS abundances in the uranium rich metal poor star CS 31082-001: Constraints on the r-Process Open

C. Siqueira-Mello, M. Spite, B. Barbuy, F. Spite, E. Caffau , et al. · 2016

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6Li/7Li isotopic ratio in the most metal-poor binary CS22876-032 Open

J. I. Gónzalez Hernández, E. Caffau, H.‐G. Ludwig, P. Bonifacio, M. Steffen , et al. · 2015

We present high-resolution and high-quality UVES spectroscopic data of the most metal-poor binary CS 22876-032 ([Fe/H] ∼ -3.7 dex) in the Li I λ 670.8 nm doublet spectral region to investigate the 6 Li/ 7 Li isotopic ratio.We add together …

HIGH-RESOLUTION ABUNDANCE ANALYSIS OF VERY METAL-POOR R-I STARS Open

Cesar Siqueira Mello, V. Hill, B. Barbuy, M. Spite, F. Spite , et al. · 2015

Context. Moderately r-process-enriched stars (r-I; +0.3 ≤ [Eu/Fe] ≤ +1.0) are at least four times as common as those that are greatly enriched in r-process elements (r-II; [Eu/Fe] > +1.0), and the abundances in their atmospheres are import…

The first generations of stars Open

E. Caffau, A. G. Gallagher, P. Bonifacio, R. Cayrel, N. Christlieb , et al. · 2015

The photospheric solar oxygen project Open

Matthias Steffen, D. Prakapavičius, E. Caffau, H.‐G. Ludwig, P. Bonifacio , et al. · 2015

\n Context. In the Sun, the two forbidden [O i] lines at 630 and 636 nm were previously found to provide discrepant oxygen abundances.\n Aims. We investigate whether this discrepancy is peculiar to the Sun or whether it is also observed in…

The photospheric solar oxygen project: IV. 3D-NLTE investigation of the 777 nm triplet lines Open

M. Steffen, D. Prakapavičius, E. Caffau, H.‐G. Ludwig, P. Bonifacio , et al. · 2015

The solar photospheric oxygen abundance is still widely debated. Adopting the solar chemical composition based on the "low" oxygen abundance, as determined with the use of three-dimensional (3D) hydrodynamical model atmospheres, results in…

TOPoS Open

P. Bonifacio, E. Caffau, M. Spite, Marco Limongi, A. Chieffi , et al. · 2015

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. We here present our analysis of six CEMP stars. Calcium and ca…

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