Evolution and Yields of Extremely Metal‐poor Intermediate‐Mass Stars

Intermediate mass stellar evolution tracks from the main sequence to the tipof the AGB for five initial masses (2 to 6Msun) and metallicity Z=0.0001 havebeen computed. The detailed 1D structure and evolution models includeexponential overshooting, mass loss and a detailed nucleosynthesis network withupdated nuclear reaction rates. The network includes a two-particle heavyneutron sink for approximating neutron density in the He-shell flash. It isshown how the neutron-capture nucleosynthesis is important in models of verylow metallicity for the formation of light neutron-heavy species, like sodiumor the heavy neon and magnesium isotopes. The models have high resolution, asrequired for modeling the third dredge-up. All sequences have been followedfrom the pre-main sequence to the end of the AGB when all envelope mass islost. Detailed structural and chemical model properties as well as yields arepresented. This set of stellar models is based on standard assumptions andupdated input physics. It can be confronted with observations ofextremely-metal poor stars and may be used to assess the role of AGB stars inthe origin of abundance anomalies of some Globular Cluster members ofcorrespondingly low metallicity.Comment: 40 pages, 11 figures, to appear in ApJS, including 5 electronic table