Dispersal of massive star products and consequences for galactic
chemical evolution
M.S. Oey
The processes that disperse the products of massive stars from their
birth sites play a fundamental role in determining
the observed abundances. I discuss parameterizations for
element dispersal and their roles in chemical evolution, with an
emphasis on understanding present-day dispersion and homogeneity in
metallicity. Turbulence dominates mixing processes, with
characteristic timescales of order 10e8 yr, implying significant
dilution of metals into the ISM. This permits a rough estimate of the
metallicity distribution function of enrichment events. Many systems,
including the Milky Way and nearby galaxies, show metallicity
dispersions that as yet appear consistent with pure inhomogeneous evolution.
There are also systems like I Zw 18 that show strong homogenization,
perhaps tied to small galaxy size, high star formation rate, and/or
superwinds.
2002, in A Massive Star Odyssey: From Main Sequence to Supernova,
eds. K. A. van der Hucht, A. Herrero, & C. Esteban,
(San Francisco: ASP), 620
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