The low-z subset of the many-multiplet data from quasar absorption systems was explained using the isotopic ratios produced by the synthesis of 25,26Mg at the base of the convective envelope in low-metallicity asymptotic giant branch stars. A model based on plausible expectations of stellar and galactic evolution was presented. Huge amounts of neutron-rich Mg isotopes were observed in metal-poor globular-cluster stars. The results show that the quasar absorption spectra may be the source of information on the nucleosynthetic history of such systems.
Bibliographical noteFunding Information:
∗ The research of this author was partially supported by National Science Foundation grant: NSF-IIS-0326387 and Air Force Office of Scientific Research (AFOSR) grant: FA9550-05-1-0454. ** Contributions to this article by co-author Leah Wong constitute an original work prepared by an officer or employee of the United States Government as part of that person's official duties. No copyright applies to these contributions.