Director, New York Center for Astrobiology (since 2008)
Rensselaer Alumni Association Outstanding Teacher’s Award recipient (2002)
Professor of Physics, Rensselaer Polytechnic Institute (since 1994)
Associate Professor of Physics, Rensselaer Polytechnic Institute (1991/94)
Professor of Astrophysics, University of Central Lancashire (1990/91)
Senior Lecturer in Astrophysics, University of Central Lancashire (1980/90)
Ph.D., Astronomy, University of St Andrews (1975)
B.Sc., Physics (Hons.), University of St Andrews (1970)
The long-term goal of my research is to test the hypothesis that organic molecules relevant to the origin of life are ubiquitous within the interstellar condensations from which planetary systems are born. The principal carriers of the biologically important chemical elements in interstellar space are submicron sized dust grains. The physical and chemical properties of these particles, and their evolution with respect to time in regions of active star formation, are vital and topical issues in modern astrophysics with potentially far-reaching implications for studies of the origin and distribution of life.
Research on star formation has been greatly stimulated in recent years by advances in infrared astronomy, providing a means of studying stellar populations deep within molecular clouds in regions hidden from view at visible wavelengths. Infrared observations also provide an extremely powerful technique for investigating the nature of interstellar dust: solid state spectral features contain a wealth of information on the composition, internal structure and thermal history of the grains. The data needed to advance this field are now widely available from ground-based telescopes and from the archives of past space missions such as the Infrared Space Observatory and the Spitzer Space Telescope. Current and future missions such as the Stratospheric Observatory for Infrared Astronomy and the James Webb Space Telescope will provide new data of unprecedented quality over the next decade and beyond.
We are carrying out a systematic study of infrared dust features in a carefully selected sample of embedded young stellar objects and distant field stars viewed through dense molecular clouds. The primary aim is to explore the evolution of icy grain mantles in the cocoons of low-mass protostars, using the field stars as the ‘control experiment’ delineating dust properties in undisturbed molecular-cloud material. Results are interpreted with reference to the optical properties of compounds synthesized in the laboratory under simulated interstellar conditions. Our observations provide detections of not only simple ices such as H2O, CO and CO2, but also organic molecules of various degrees of complexity and oxidation state, including CH4, CH3OH, H2CO, HCOOH, OCN, and more complex hydrocarbons and kerogens. This program of research will lead to a clear understanding of the evolution of organic matter in the environments of young stars that are realistic analogs of the early Solar System, thus shedding new light on our own origins and simultaneously providing insight into the probability that conditions leading to life arose elsewhere.
This research is being carried out in collaboration with groups at the NASA Ames Research Center, the SETI Institute, the University of Missouri at St Louis, the University of Virginia, the University of Helsinki, and the University of Hertfordshire.