6Li in metal-poor halo stars: real or spurious? (2009)
Steffen, M., Cayrel, R., Bonifacio, P., Caffau, E.
The presence of convective motions in the atmospheres of metal-poor halo stars leads to systematic asymmetries of the emergent spectral line profiles. Since such line asymmetries are very small, they...
Effects of granulation on neutral copper resonance lines in metal-poor stars (2009)
We make use of three dimensional hydrodynamical simulations to investigate the effects of granulation on the Cu I lines of Mult. 1 in the near UV, at 324.7 nm and 327.3 nm. These lines remain strong...
Lithium abundances of Main Sequence and Sub-Giant stars in the Globular Cluster NGC 6397 (2009)
Hernández, J. I. González, Bonifacio, P., Caffau, E., Steffen, M., Behara, N., ...
We present FLAMES/GIRAFFE spectroscopy obtained at the Very Large Telescope (VLT). Using these observations we have been able for the first time to observe the Li I doublet in the Main Sequence stars...
A view of the Galactic halo using beryllium as a time scale (2009)
Smiljanic, Rodolfo, Pasquini, L., Bonifacio, P., Galli, D., Barbuy, B., Gratton, R., ...
Beryllium stellar abundances were suggested to be a good tracer of time in the early Galaxy. In an investigation of its use as a cosmochronometer, using a large sample of local halo and thick-disk...
Lithium in the Globular Cluster NGC 6397: Evidence for dependence on evolutionary status (2009)
Hernandez, J. I. Gonzalez, Bonifacio, P., Caffau, E., Steffen, M., Behara, N. T., ...
Most Globular Clusters are believed to host a single stellar populations. They can thus be considered a good place to study the Spite plateau and probe for possible evolutionary modifications of the...
Detailed analyses of three neutron-capture-rich carbon-enhanced metal-poor stars (2009)
Behara, N. T., Bonifacio, P., Sbordone, L., Hernandez, J. I. Gonzalez, Caffau, E.
Approximately 20% of very metal-poor stars ([Fe/H] < -2.0) are strongly enhanced in carbon ([C/Fe] > +1.0). Such stars are referred to as carbon-enhanced metal-poor (CEMP) stars. We present a...
The CIFIST 3D model atmosphere grid (2009)
Caffau, E., Steffen, M., Freytag, B., Bonifacio, P., Kucinskas, A.
Grids of stellar atmosphere models and associated synthetic spectra are numerical products which have a large impact in astronomy due to their ubiquitous application in the interpretation of...
Impact of granulation effects on the use of Balmer lines as temperature indicators (2009)
Behara, N. T., Steffen, M., Bonifacio, P.
Balmer lines serve as important indicators of stellar effective temperatures in late-type stellar spectra. One of their modelling uncertainties is the influence of convective flows on their shape. We...
Sulphur in the Globular Clusters 47 Tucanae and NGC 6752 (2009)
Sbordone, L., Limongi, M., Chieffi, A., Caffau, E., Bonifacio, P.
The light elements Li, O, Na, Al, and Mg are known to show star to star variations in the globular clusters 47 Tuc and NGC 6752. Such variations are interpreted as due to processing in a previous...
Bonifacio, P., Spite, M., Cayrel, R., Hill, V., Spite, F., Francois, P., ...
CONTEXT:The detailed chemical abundances of extremely metal-poor (EMP) stars are key guides to understanding the early chemical evolution of the Galaxy. Most existing data are, however, for giant...
Caffau, E., Maiorca, E., Bonifacio, P., Faraggiana, R., Steffen, M., ...
CONTEXT: In recent years, the solar chemical abundances have been studied in considerable detail because of discrepant values of solar metallicity inferred from different indicators, i.e., on the one...
Andrievsky, S. M., Spite, M., Korotin, S. A., Spite, F., Francois, P., Bonifacio, P., ...
Barium is a key element in constraining the evolution of the (not well understood) r-process in the first galactic stars and currently the Ba abundances in these very metal-poor stars were mostly...
Beryllium abundances and star formation in the halo and in the thick disk (2009)
Smiljanic, R., Pasquini, L., Bonifacio, P., Galli, D., Gratton, R. G., Randich, S., ...
[abridged] Beryllium is a pure product of cosmic ray spallation. This implies a relatively simple evolution in time of the beryllium abundance and suggests its use as a time-like observable. We study...
Solar analogues in open clusters: The case of M67 (2009)
Biazzo, K., Pasquini, L., Bonifacio, P., Randich, S., Bedin, L. R.
Solar analogues are fundamental targets for a better understanding of our Sun and our Solar System. Usually, this research is limited to field stars, which offer several advantages and limitations....
A new implementation of the infrared flux method using the 2MASS catalogue (2009)
Hernández, J. I. González, Bonifacio, P.
We present a new implementation of the infrared flux method (IRFM) using the 2MASS catalogue. We compute the theoretical quantities in the 2MASS JHKs filters by integrating theoretical fluxes...
Andrievsky, S.M., Spite, M., Korotin, S. A., Spite, F., Francois, P., Bonifacio, P., ...
Barium is a key element in constraining the evolution of the (not well understood) r-process in the first galactic stars and currently the Ba abundances in these very metal-poor stars were mostly...
Andrievsky, S.M., Spite, M., Korotin, S. A., Spite, F., Francois, P., Bonifacio, P., ...
Barium is a key element in constraining the evolution of the (not well understood) r-process in the first galactic stars and currently the Ba abundances in these very metal-poor stars were mostly...
Extremely metal-poor stars from the SDSS (2008)
Bonifacio, P., Caffau, E., Behara, N. T., Hernandez, J. I. Gonzalez, Sbordone, L.
We give a progress report about the activities within the CIFIST Team related to the search for extremely metal-poor stars in the Sloan Digital Sky Survey's spectroscopic catalog. So far the search...
Andrievsky, S.M., Spite, M., Korotin, S.A., Spite, F., Bonifacio, P., Cayrel, R., ...
Aims: {Aluminium is a key element to constrain the models of the chemical enrichment and the yields of the first supernovae. But obtaining precise Al abundances in extremely metal-poor (EMP) stars...
Andrievsky, S.M., Spite, M., Korotin, S.A., Spite, F., Bonifacio, P., Cayrel, R., ...
Aims: {Aluminium is a key element to constrain the models of the chemical enrichment and the yields of the first supernovae. But obtaining precise Al abundances in extremely metal-poor (EMP) stars...
Caffau, Elisabetta, Sbordone, L., Bonifacio, P., Steffen, M., Behara, N.T.
Context: The stable element hafnium (Hf) and the radioactive element thorium (Th) were recently suggested as a suitable pair for radioactive dating of stars. The applicability of this elemental pair...
Caffau, Elisabetta, Sbordone, L., Bonifacio, P., Steffen, M., Behara, N.T.
Context: The stable element hafnium (Hf) and the radioactive element thorium (Th) were recently suggested as a suitable pair for radioactive dating of stars. The applicability of this elemental pair...
Spectral analyses of three carbon-enhanced metal-poor stars (2008)
Behara, N.T., Bonifacio, P., Sbordone, L., Gonzalez Hernandez, J.I., Caffau, E.
We are conducting a high-resolution follow-up of candidate EMP stars extracted from the Sloan Digital Sky Survey (SDSS; York et al.~2000) using UVES at the VLT. Three of the programme stars, SDSS...
Spectral analyses of three carbon-enhanced metal-poor stars (2008)
Behara, N.T., Bonifacio, P., Sbordone, L., Gonzalez Hernandez, J.I., Caffau, E.
We are conducting a high-resolution follow-up of candidate EMP stars extracted from the Sloan Digital Sky Survey (SDSS; York et al.~2000) using UVES at the VLT. Three of the programme stars, SDSS...
UVES observations of QSO 0000-2620 : Molecular hydrogen abundance in the damped (2007)
System At Levshakov, S. A. Levshakov, P. Molaro, P. Bonifacio, G. Vladilo
. We have discovered molecular hydrogen in a fourth quasar damped Ly system (hereafter DLA). The UVES spectrograph on the 8.2m ESO Kueyen telescope has allowed the detection of H 2 in gas with low...
Doi Eso Astronomy, P. Bonifacio, L. Pasquini, A. Bragaglia, E. Carretta, M. Centurion, ...
We make use of high resolution, high signal-to-noise ratio spectra of 12 turn-o# stars in the metal-poor globular cluster NGC 6397 to measure its lithium content. We conclude that they all have the...
The O-Na and Mg-Al Anticorrelations in Turn-Off and early Subgiants in Globular Clusters (2000)
Gratton, R. G., Bonifacio, P., Bragaglia, A., Carretta, E., Castellani, V., Centurion, M., ...
High dispersion spectra (R>40,000) for a quite large number of stars at the main sequence turn-off and at the base of the subgiant branch in NGC6397 and NGC6752 were obtained with the UVES on Kueyen...