Grauer will use time-series photometry to study the late stages of stellar evolution, from the planetary nebula ejection phase through the white dwarf cooling phases. He will be focusing on the central stars of planetary nebulae, variable white dwarfs, and binary stars. He will be using a new portable two-star photometer, which he helped develop (National Science Foundation (NSF) Grant AST 87-12249) and which he will be using at several observatories in the United States and abroad. Furthermore, he will be participating in the Extended Coverage Network, which is an international effort of observing variable stars from observatories around the globe in order to be independent of the local diurnal cycle. One of the central topics studied by astronomers is the birth, evolution, and death of stars. Grauer will focus on the final stages in the evolution of stars, when many of them shed their outer layers forming so-called planetary nebulae (objects unrelated to planets). The stars remaining after the loss of their outer layers contract into extremely compact objects, called white dwarfs, with masses comparable to that of the sun and sizes like the Earth's. Some of the white dwarfs pulsate, with periods of the order of minutes. They also are found in close proximity of other stars, with both stars orbiting about each other with periods of the order of hours. The efficient observing of such pulsating and orbiting stars requires special observing equipment and techniques, both of which Grauer possesses. Grauer will be involving undergraduate students under NSF's Research for Undergraduate Institutions (RUI) Program.
