• DOI:10.1086/588811
• Corpus ID: 118563048

Detailed Abundances for 28 Metal-poor Stars: Stellar Relics in the Milky Way

@article{Lai2008DetailedAF,
  title={Detailed Abundances for 28 Metal-poor Stars: Stellar Relics in the Milky Way},
  author={David K. Lai and Michael J. Bolte and Jennifer A. Johnson and Sara Lucatello and Alexander Heger and S. E. Woosley},
  journal={The Astrophysical Journal},
  year={2008},
  volume={681},
  pages={1524 - 1556}
}

• David K. Lai, M. Bolte, +3 authors S. Woosley
• Published 8 April 2008
• Physics
• The Astrophysical Journal

We present the results of an abundance analysis for a sample of stars with –4 < [ Fe/H ] < − 2. The data were obtained with the HIRES spectrograph at Keck Observatory. The set includes 28 stars, with effective temperature ranging from 4800 to 6600 K. For 13 stars with [ Fe/H ] < − 2.6, including nine with [ Fe/H ] < − 3.0 and one with [ Fe/H ] = − 4.0, these are the first reported detailed abundances. For the most metal-poor star in our sample, CS 30336–049, we measure an abundance pattern that is very similar to stars in the range [ Fe/H ] ∼ − 3.5, including a normal C + N abundance. We also find that it has very low but measurable Sr and Ba, indicating some neutron-capture activity even at this low of a metallicity. We explore this issue further by examining other very neutron capture-deficient stars and find that, at the lowest levels, [Ba/Sr] exhibits the ratio of the main r-process. We also report on a new r-process-enhanced star, CS 31078–018. This star has [ Fe/H ] = − 2.85, [ Eu/Fe ] = 1.23, and [ Ba/Eu ] = − 0.51. CS 31078–018 exhibits an “actinide boost,” i.e., much higher [Th/Eu] than expected and at a similar level to CS 31082–001. Our spectra allow us to further constrain the abundance scatter at low metallicities, which we then use to fit to the zero-metallicity Type II supernova yields of Heger & Woosley (2008). We find that supernovae with progenitor masses between 10 and 20 M☉ provide the best matches to our abundances.