Shipman shall continue his theoretical research on the chemical compositions of white-dwarf atmospheres. The emphasis will be on interrelating the observed abundance patterns via evolution and accretion processes, using appropriate models of the white-dwarf atmospheres. The research involves numerous collaborators. When stars like the Sun exhaust their nuclear energy sources, they shrink to about the size of the Earth. New observations of such stars, called white dwarfs, show that the chemical abundances in their outer layers are much more varied than expected. A good interpretation of these observations promises a much improved understanding of just how solar-like stars become white dwarfs. Shipman will interpret the observations using models of the stars, of their atmospheres, and of gases that may accrete from companion stars.
