Help Privacy Policy Disclaimer
  Advanced SearchBrowse




Journal Article

The Hamburg/ESO R-process Enhanced Star survey (HERES)


Kratz,  K. L.
Biogeochemistry, Max Planck Institute for Chemistry, Max Planck Society;

External Resource
No external resources are shared
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available

Hill, V., Christlieb, N., Beers, T. C., Barklem, P. S., Kratz, K. L., Nordström, B., et al. (2017). The Hamburg/ESO R-process Enhanced Star survey (HERES). Astronomy and Astrophysics, 607: A91. doi:10.1051/0004-6361/201629092.

Cite as: https://hdl.handle.net/11858/00-001M-0000-002E-962C-F
We report an abundance analysis for the highly r-process-enhanced (r-II) star CS 29497-004, a very metal-poor giant with solar system Teff = 5013 K and [Fe/H] = −2.85, whose nature was initially discovered in the course of the HERES project. Our analysis is based on high signal-to-noise ratio, high-resolution (R ~ 75 000) VLT/UVES spectra and MARCS model atmospheres under the assumption of local thermodynamic equilibrium, and obtains abundance measurements for a total of 46 elements, 31 of which are neutron-capture elements. As is the case for the other ~25 r-II stars currently known, the heavy-element abundance pattern of CS 29497-004 well-matches a scaled solar system second peak r-process-element abundance pattern. We confirm our previous detection of Th, and demonstrate that this star does not exhibit an “actinide boost”. Uranium is also detected (log ϵ(U) = −2.20 ± 0.30), albeit with a large measurement error that hampers its use as a precision cosmo-chronometer. Combining the various elemental chronometer pairs that are available for this star, we derive a mean age of 12.2 ± 3.7 Gyr using the theoretical production ratios from published waiting-point approximation models. We further explore the high-entropy wind model (Farouqi et al. 2010, ApJ, 712, 1359) production ratios arising from different neutron richness of the ejecta (Ye), and derive an age of 13.7 ± 4.4 Gyr for a best-fitting Ye = 0.447. The U/Th nuclei-chronometer is confirmed to be the most resilient to theoretical production ratios and yields an age of 16.5 ± 6.6 Gyr. Lead (Pb) is also tentatively detected in CS 29497-004, at a level compatible with a scaled solar r-process, or with the theoretical expectations for a pure r-process in this star.