Short-lived nuclei in the early solar system and a diversity of r-processes

Abstract

It is established that Pu-244, Hf-182, I-129, Pd-107, Fe-60, Mn-53, Ca-41, and Al-26 were present in the early solar system. Several stellar sources are responsible for producing these nuclei. Short-lived Al-26 and Ca-41 require a very late stage injection into the proto-solar nebula and rapid accretion of the sun (~7x10^(25)y). I-129 is produced only by the r-process in low abundance, requiring long term contributions to the solar nebula cease ~10^8 y prior to collapse. In contrast, Hf-182, with a larger-process component, is in high abundance, requiring a time scale of ~10^7 y. This discrepancy requires distinctive SN sites for production of the r-process. Furthermore, from neutrino interactions competing with beta decays, the two r-processes cannot be produced in a single scenario. Using the results of Richter, Ott, and Begemann and considering neutrino spallation reactions during post processing, we calculate the dynamic scale for SNII to be tau < 0.85 s.

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