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Marc Airhart (primary)


Christopher A Sneden

Professor, Department of Astronomy, College of Natural Sciences

Phone: +1 512 471 1349, +1 512 471 3000

Chris Sneden earned a B.A. at Haverford College in 1969 and a Ph.D. from The University of Texas at Austin in 1973. He has been a member of the UT Austin faculty since 1979 and since 1999 has held the post of Rex G. Baker, Jr. and McDonald Observatory Centennial Professor of Astronomy. Sneden currently serves as Editor of The Astrophysical Journal Letters, and has served on many review panels and committees for NASA and the National Science Foundation's national observatories. He was the chairman of the astronomy department from 1998 to 2003.

As an observational astronomer, Sneden uses the telescopes of McDonald Observatory and the national observatories to gather astronomical data for analysis. He concentrates on using a high-resolution spectrograph to spread stellar light into component wavelengths, in order to study the absorptions of light at selected portions of the gathered spectrum. The chief goal of his analysis is to deduce the chemical composition of a star. The interest here is in the realization that stars synthesize all the heavy elements in their deep interiors, where temperatures and pressures are extremely high, large enough to force fusion of light atomic nuclei into heavier ones. Such nuclear fusion is responsible for the creation of the elements on the periodic table, and by implication is one of the reasons we have life on earth -- no stellar fusion, no elements such as carbon upon which life is based. Out of the trillions of stars in our galaxy, Sneden concentrates on those of the Milky Way's galactic halo. This halo of stars surrounds the familiar disk of the Milky Way. Halo stars are the oldest in the galaxy. Since they were born in an earlier stellar generation they do not have as many of the heavy elements as does our Sun and solar system. Comparing the detailed chemical compositions of galactic halo stars with the stars of the galactic disk near the Sun can tell us the history of heavy element buildup in the galaxy, and even indicate the age of the galaxy.


Astronomy, spectroscopy of stars; chemical compositions of stars; evolution of the Milky Way galaxy; the life cycles of stars