PhD, University of Wisconsin-Madison, 1966
- Interstellar medium
- Halo stars
- Primordial nucleosynthesis
My research interests have focussed primarily on three different topics. 1) With a number of collaborators, I've measured the absorption of the light received from individual stars in the Galaxy and in the Magellanic Clouds by the interstellar gas in all three systems, in order to deduce and to compare some of the fundamental properties of the gas and dust in these quite different galaxies. HST observations have played an important role in this work. 2) With collaborators, I've also measured the abundances of lithium, beryllium, and boron preserved in the surface layers of suitably unevolved Galactic stars with a wide range of ages, including some of the oldest stars. Those results illuminate the cosmic production and destruction of the light elements, from a few minutes after the Big Bang to the present time, and they test observationally the standard picture of the early universe. 3) Again with collaborators, I've measured some properties of the gaseous (and dusty) debris disk that surrounds the nearby, young star Beta Pictoris -- and, less extensively, of those that surround other apparently similar stars. The high spatial resolution with which such nearby disks can be studied may illuminate important features of the disk in which the solar system originally formed.