Joined UW in
Professor Wallerstein’s research is oriented around the chemical composition of stellar atmospheres. These are important clues to the composition to the origin of the star and its evolution. Stars reflect the environments of their formation by the composition of the gasses in their atmospheres. For example, stars formed 10-15 billion years ago in globular clusters show that these clusters ceased to produce the heavy elements seen in the Sun after only 1 percent of the solar level of heavies were produced. Other stellar atmospheres show a composition which was changed by nuclear reactions in their interiors. Prof. Wallerstein works closely with his students in observations at the telescope and the analysis of these data using computer models of stellar atmospheres. They interpret their data in terms of theories of stellar structure and core nuclear burning. Prof. Wallerstein also studies the structure of the interstellar medium through emission and absorption lines.