Effects on Supernovae and their Remnants of Asymmetric Envelopes Caused by Outflow from Binary-star Progenitors

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The violent star explosions, known as supernovae, are responsible formany features of our Universe. They produce and distribute many ofthe heavy elements that make up stars, new planets, and also people.The energy supernovae release into the interstellar gas heats and stirs it,and some of that energy goes to accelerating a few subatomic particlesto extreme energies -- the enigmatic cosmic rays that fill our Galaxyand constantly rain down on the Earth. In the last few thousand years,several Galactic supernovae were visible at Earth and carefullyrecorded by naked-eye observers. The remnants of those supernovae,expanding gas clouds emitting radio waves, X-rays, and visible light,can now be studied in detail, along with hundreds of older remnantsfrom supernovae too distant to be seen on Earth with the nakedeye. This proposal will model the effects of supernovae that occur in systems with two stars gravitationally bound to each other. Recent evidence suggests that many supernovae originate in binary systems, pairs of stars orbiting one another. The more massive stars shed material as they age, particularly in the stages just prior to explosion, so the explosions take place in a complicated environment of gas. These investigators will computestate-of-the-art simulations of pre-supernova environments, and then modelthe explosion, to see what effects it has on the appearance of the supernovae at the time of the event, and on the remnants of the events, which are stillthousands of years later. The investigators hope to identify particular features that such supernovaeand remnants might show that would be clues to the environments thatgave rise to them. In addition, a few particular objects, such ashistorical remnants from supernovae seen at Earth in the last fewhundred years, will be studied, to try to identify the types of stars that created the explosions.The investigators will use high-performance computing systems at national facilities, and will train students in the most up-to-date applications of computing to complex problems. Improving our understanding of supernovae adds anessential piece to the grand narrative of the nature of our Universeand the place of humanity in it.