Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-05-03
Astronomy and Astrophysics
Astrophysics
Accepted for A&A; 31 pages, 2 electronic tables presently available at http://www.astro.uu.se/~barklem/papers/heres_tables.tar
Scientific paper
10.1051/0004-6361:20052967
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 spectra are analysed using an automated line profile analysis method based on the Spectroscopy Made Easy codes of Valenti & Piskunov. Elemental abundances of moderate precision have been obtained for 22 elements, C, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, and Eu, where detectable. Among the sample of 253 stars, we find 8 r-II stars and 35 r-I stars. We also find three stars with strong enhancements of Eu which are s-process rich. A significant number of new very metal-poor stars are confirmed: 49 stars with [Fe/H] < -3 and 181 stars with -3 < [Fe/H] < -2. We find one star with [Fe/H] < -3.5. We find the scatter in the abundance ratios of Mg, Ca, Sc, Ti, Cr, Fe, Co, and Ni, with respect to Fe and Mg, to be similar to the estimated relative errors and thus the cosmic scatter to be small, perhaps even non-existent. The elements C, Sr, Y, Ba and Eu, and perhaps Zr, show scatter at [Fe/H] < -2.5 significantly larger than can be explained from the errors in the analysis, implying scatter which is cosmic in origin. Significant scatter is observed in abundance ratios between light and heavy neutron-capture elements at low metallicity and low levels of r-process enrichment. (*** abridged ***)
Barklem Paul S.
Beers Timothy C.
Bessell Michael S.
Christlieb Nn.
Hill Vanessa
No associations
LandOfFree
The Hamburg/ESO R-process Enhanced Star survey (HERES) II. Spectroscopic analysis of the survey sample does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Hamburg/ESO R-process Enhanced Star survey (HERES) II. Spectroscopic analysis of the survey sample, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Hamburg/ESO R-process Enhanced Star survey (HERES) II. Spectroscopic analysis of the survey sample will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-461037