a1 Department of Asronomy and Astrophysics, UCSC Santa Cruz, CA 95064, USA email: firstname.lastname@example.org
a2 School of Physics & Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA email: email@example.com
a3 Nuclear Computational Physics Group, Physics and Life Sciences Directorate, LLNL, Livermore, CA, 94550, USA email: firstname.lastname@example.org
Today we understand, to reasonable accuracy, the origin of most of the abundant elements in the sun and similar Population I stars. Given our relatively primitive ability to model supernova explosion mechanisms, stellar mass loss, and stellar mixing, this is a remarkable achievement. This understanding is possible, in part, because supernovae are highly constrained by their spectra, light curves and the sorts of remnants they leave. This same understanding extends to the major abundances seen in primitive metal-poor stars down to [Fe/H] > −4. In particular, one finds no compelling evidence for exotic energies or unusual stellar properties. There are exceptions, however. About half of the isotopes above iron, the r-process and the p-process with A < 130, still have an uncertain origin, both in the sun and in metal-poor stars. The abundances in the hyper-iron-poor stars ([Fe/H] < −4) also require a special explanation. We suggest that they represent the operation of a first generation of massive stars that produced almost exclusively C, N, and O and black holes, a generation in which 100 M were abundant, but stars over about 150 M and under 30 M were almost absent.