11 research outputs found
Massive Star Evolution: Nucleosynthesis and Nuclear Reaction Rate Uncertainties
We present a nucleosynthesis calculation of a 25 solar mass star of solar
composition that includes all relevant isotopes up to polonium. In particular,
all stable isotopes and necessary nuclear reaction rates are covered. We follow
the stellar evolution from hydrogen burning till iron core collapse and
simulate the explosion using a ``piston'' approach. We discuss the influence of
two key nuclear reaction rates, C12(a,g) and Ne22(a,n), on stellar evolution
and nucleosynthesis. The former significantly influences the resulting core
sizes (iron, silicon, oxygen) and the overall presupernova structure of the
star. It thus has significant consequences for the supernova explosion itself
and the compact remnant formed. The later rate considerably affects the
s-process in massive stars and we demonstrate the changes that different
currently suggested values for this rate cause.Comment: 6 pages, including 4 PostScript figures, to appear in Proc.
"Astronomy with Radioactivities III", New Astronomy Review