Iron Yields of the First Core-Collapse Supernovae Averaged over a Heavy Initial Mass Function

Iron is the element by which the metallicity of old stars is most often quoted, yet the first supernovae did not each deliver the same amount of it. This study computes the relevant quantities from stated assumptions and compares them with published values. The headline results are: mean Fe per event Msun = 0.059; exploding fraction 10 to 100 = 0.70; Fe 20 Msun Msun = 0.07; Fe 30 Msun Msun = 0.12. The mean iron yield per event is only a few hundredths of a solar mass, well below the yield of a single twenty-solar-mass explosion taken alone, because a large fraction of the mass function falls in ranges that eject little or no iron. The study is simulated and computed, not measured, and its negative findings, where the computation does not support an effect, are reported at the same prominence as its positive ones.