Heavy elements from black hole-neutron star mergers

Matter flung out into space during black hole-neutron star mergers may well be one of the major contributors to the "r-process" heavy-elements in the universe such as gold and lead.  To test this idea, we calculated the nuclear reactions taking place in the ejected matter from our black hole -neutron star mergers using the "SkyNet" nucleosynthesis code written by SXS member Jonas Lippuner.  Our first studies found that it is very easy for our ejecta to produce the high-mass r-process elements (in abundance ratios not terribly different from what's in the sun), but very little of the low-mass r-process elements are made, meaning they would have to come from a different source.  We then found that this underproduction can be ameliorated (but not removed) by the effect of neutrinos given off by the merger remnant being absorbed by the outgoing matter, which changes its composition.  Read the paper here (http://arxiv.org/abs/1601.07942).

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Inspiration

Go, wond'rous creature!
Mount where Science guides,
Go, measure earth, weigh air,
    and state the tides;
Instruct the planets in
    what orbs to run,
Correct old Time,
    and regulate the Sun.

Alexander Pope's
An Essay on Man

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About SXS

The SXS project is a collaborative research effort involving multiple institutions. Our goal is the simulation of black holes and other extreme spacetimes to gain a better understanding of Relativity, and the physics of exotic objects in the distant cosmos.

The SXS project is supported by Canada Research Chairs, CFI, CIfAR, Compute Canada, Max Planck Society, NASA, NSERC, the NSF, Ontario MEDI, the Sherman Fairchild Foundation, and XSEDE.

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