English

The r-Process and Chronometers

Astrophysics 2007-05-23 v1

Abstract

We present detailed abundance observations of the metal-poor ([Fe/H] = --2.0) Galactic halo star BD+17 3248. We have detected gold in this star, for the first time in any halo star. We also detected a weak line at 3859.60 A in the spectrum of BD+17 3248 that we tentatively identify with uranium. This would be only the second such detection of this radioactive element in any metal-poor halo stars. Similarly to the case of CS 22892--052, the heavier n-capture elements (Z >= 56) fall on the scaled solar system r-process abundance curve, while the elements with Z = 40--50 in BD+17 3248 fall below that same solar curve. Employing the newly detected Th, U and third r-process peak element (e.g., Pt, Ir) abundances, chronometric age estimates have been made for BD+17 3248. The average value of the various chronometric pairs suggests an age of 13.8 +/- 4 Gyr for this star, consistent, within error limits, with other chronometric age determinations for metal-poor Galactic halo stars.

Keywords

Cite

@article{arxiv.astro-ph/0204294,
  title  = {The r-Process and Chronometers},
  author = {John J. Cowan and Christopher Sneden and James W. Truran},
  journal= {arXiv preprint arXiv:astro-ph/0204294},
  year   = {2007}
}

Comments

4 pages, 2 figures; In Proceedings of the 11th Workshop on Nuclear Astrophysics, eds. W. Hillebrandt and E. Muller, p. 176

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