Summary of Nucleosynthesis Results


Based on some simple calcuations, we have assembled here some plots of yields, based on the published results from Heger and Woosley (2007), which includes yields for solar metallicity and masses ranging from 15 to 40 solar masses.The results are preliminary, but show at high masses a large production of Carbon, which can produce an upturn of [C/O] for massive star yields.I suspect that our observations with Keck/ESI are detecting this upturn. However I also welcome suggestions on how to improve the models, and especially how to include more massive stars and low metallicity yields.
Detailed results from the analysis are below.



Initial test of yields within a star using one of the Heger and Woosley yield files. Shows [C/O] vs zone number for a massive star.
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Plot of total abundances for a set of massive stars, with different lines showing yields for different masses. Note that only the bottom trace (M=40Msol) gives more C than O.
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Trend in [C/H] within yields of massive stars. Note switch at M=40 solar masses --> more C than O produced!
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Trend in [C/H] within yields of massive stars. Note switch at M=40 solar masses --> more C than O produced!
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Mass of stars blowing up as a function of time; at present I only have included masses < 40 for my model..
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IMF used in my model. Uses a Salpeter IMF with N(M) = M^-1.5; this one shows N(M)*M, to get total stellar mass vs mass
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Using the IMF and turnoff mass vs time (assuming a spike of star formation at t=0) produces the following [C/O] vs time
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Changing the x axis from time to [O/H] shows that [C/O] does turn up at low metallicity
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Different species will be enriched at different rates in my model. This shows various [X/H] vs time.
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Enrichment as a function instead of [O/H]
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Enrichment of various elements [X/Si] as a function instead of [Si/H]. Should show upturn in [O/Si] vs [Si/H] as seen in paper
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Contribution of Type II supernovae to IGM as a function of time in our model
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Contribution of stellar winds to IGM as a function of time in our model
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Web site and analysis software developed by Dr. Bryan E. Penprase, Pomona College. 
email: bpenprase@pomona.edu