# Iron-Peak Element Abundances in Warm Very Metal-Poor Stars

**Authors:** Christopher Sneden, Ann Merchant Boesgaard, John J. Cowan, Ian U. Roederer, Elizabeth A. Den Hartog, James E. Lawler  
**arXiv:** [2304.06899](https://arxiv.org/abs/2304.06899)  
**Date:** 2023-04-14  
**Summary page:** https://www.summarizepaper.com/fr/paper/2304.06899v1/

## Abstract

We have derived new detailed abundances of Mg, Ca, and the Fe-group elements Sc through Zn (Z = 21-30) for 37 main sequence turnoff very metal-poor stars ([Fe/H] <= -2.1). We analyzed Keck HIRES optical and near-UV high signal-to-noise spectra originally gathered for a beryllium abundance survey. Using typically about 400 Fe-group lines with accurate laboratory transition probabilities for each star, we have determined accurate LTE metallicities and abundance ratios for neutral and ionized species of the 10 Fe-group elements as well as alpha elements Mg and Ca. We find good neutral/ion abundance agreement for the 6 elements that have detectable transitions of both species in our stars in the 3100-5800 Angstrom range. Earlier reports of correlated Sc-Ti-V relative overabundances are confirmed, and appear to slowly increase with decreasing metallicity. To this element trio we add Zn; it also appears to be increasingly overabundant in the lowest metallicity regimes. Co appears to mimic the behavior of Zn, but issues surrounding its abundance reliability cloud its interpretation.