Roger Chevalier, W.H. Vanderbilt Professor of Astromony, has recently been awarded one of the most prestigious annual prizes given by the American Astronomy Society and American Institute of Physics, and is the only one given jointly by the two societies. He is being honored for his fundamental contributions to the quantitative physics of the violent and complicated life history of supernovae.
     Supernovae are powerful stellar explosions which can outshine an entire galaxy in their early phases, and provide power for hot gas in galaxies and for galactic winds. Chevalier analyses the light emissions that these phenomena generate, and most notably, has worked on the interpretation of data relating to Supernova 1987A which exploded nearly ten years ago in the Large Magellanic Cloud, a companion galaxy to ours. He has made predictions about what to expect when the effects of the explosion reach dense gas around this rapidly evolving object.
     Some of this work has been done in collaboration with astronomers and astrophysicists in Sweden, Chile, and the United States. Their information is obtained from the Hubble Space Telescope and from earth-based telescopes. Chevalier and his colleagues around the world interpret this data to make predictions about the most likely course of events in the life of these exploding stars.