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Project Progress

Collaborating investigator Patrick Young and graduate student Carola Ellinger with support from outside collaborators at the University of Arizona and Los Alamos National Laboratory have published 3D simulations of a core collapse supernova of a massive star. These simulations combined with 1D models for a range of stars were used to identify the production sites of ²⁶Al and its potential tracers. We find that the sulfur to silicon ratio in supernova ejecta correlates strongly with production of ²⁶Al. Phosphorus is produced under the same conditions, so we have an indication that solar systems enriched by ²⁶Al from supernovae will also be enriched in P. The total amount of S and Si injected into a protoplanetary system is likely to be small compared to the mass of the disk, so it will be difficult to identify candidate systems on the basis of the S/Si ratio alone, especially if there is substantial variation in abundances between stars already. We should, however, be able to identify ejecta in young supernova remnants that are rich in ²⁶Al, and use those clumps of material as constraints on models of injection into protoplanetary disks.

Working with co-I Steven Desch we also find that comparison of oxygen isotopes in solar wind and model supernovae are compatible with injection of ²⁶Al into the early solar system. Calculations of a 3D explosion of a 15 solar mass star are in progress. Our code has been updated with an improved nuclear reaction network and cooling to model formation of the dense clumps that may participate in element injection. Medium resolution (107 particles) simulations compare models with and without cooling. We plan to have a flagship 108 particle simulation completed by the end of the calendar year.

Young and student Mike Pagano with collaborators at the University of Rochester will measure and analyze the amount of enrichment by supernovae of triggered star formation regions in the Scorpius-Centaurus stellar association. The amount of enrichment will provide limits on the efficiency of incorporation of supernova material into forming planetary systems, and its spatial heterogeneity will constrain how uniformly supernovae enrich their local environment.