Astronomy and Astrophysics – Astrophysics
Scientific paper
2001-03-14
Astronomy and Astrophysics
Astrophysics
6 pages, 3 figures; To appear in the proceedings of the 20th Texas Symposium on Relativistic Astrophysics, J. C. Wheeler & H.
Scientific paper
10.1063/1.1419577
Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations demonstrate that the earliest generations of stars in the Galaxy, responsible for neutron-capture synthesis and the progenitors of the halo stars, were rapidly evolving. Abundance comparisons among several halo stars show that the heaviest neutron-capture elements (including Ba and heavier) are consistent with a scaled solar system r-process abundance distribution, while the lighter such elements do not conform to the solar pattern. These comparisons suggest two r-process sites or at least two different sets of astrophysical conditions. The large star-to-star scatter observed in the neutron-capture/iron ratios at low metallicities -- which disappears with increasing [Fe/H] -- suggests an early, chemically unmixed and inhomogeneous Galaxy. The stellar abundances indicate a change from the r-process to the slow neutron capture (i.e., s-) process at higher metallicities in the Galaxy. The detection of thorium in halo and globular cluster stars offers a promising, independent age-dating technique that can put lower limits on the age of the Galaxy.
Cowan John J.
Sneden Chistopher
Truran Jame. W.
No associations
LandOfFree
The Early Formation, Evolution and Age of the Neutron-Capture Elements in the Early Galaxy 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 Early Formation, Evolution and Age of the Neutron-Capture Elements in the Early Galaxy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Early Formation, Evolution and Age of the Neutron-Capture Elements in the Early Galaxy will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-565699