Physics Colloquium, January 14, 2003

The Chemistry of Protoplanetary Disks

Eric Herbst

The Ohio State University

The role of molecules in the study of many different types of objects in the universe is becoming recognized by all but the most myopic astronomers. Molecular spectra are detected in objects as diverse as interstellar clouds and the envelopes of old stars, and these spectra tell us details of the physical conditions in which they arise. To use molecules as detailed probes not only of present conditions, but of the history of the sources, it is necessary to understand how these molecules are produced and destroyed.

Molecular spectra give us a particularly detailed view of the stages of star formation, a process that occurs deep within interstellar clouds in our own galaxy and others. During a late stage in the formation of stars, the adolescent objects are surrounded by dense, optically thick disks. "Protoplanetary" disks are clearly the precursors of planetary systems and are therefore of great interest. The molecular spectra emanating from these objects, when interpreted with chemical modelling, indicate that the disks are rather complex, inhomogeneous objects in which incipient planets are being formed.

3.30 p.m., Smith Laboratory, Room 1005

Refreshments served in Smith 1094 at 3:00 p.m.