Scientific Programs and Opportunities

Formation of the Elements

1Deuterium Abundance

"The study of the origin of the chemical elements embraces both nearby stars and galaxies and the most distant quasars we can observe. The properties of stars and the interstellar gas in our own Galaxy and nearby galaxies enable us to probe the way in which the chemical elements are built up through the cosmic cycle of the birth, life, and death of stars in systems at the present time. The study of similar processes, but at much earlier cosmological epochs, can be carried out by observing the chemical abundances of the elements in those galaxies which can be observed in absorption against the continuum emission of the most distant quasars. These absorption systems provide important clues about the build up of chemical elements in systems which are only about one fifth the present age of the Universe and so enable us to track the chemical evolution of galaxies over long cosmological timescales. The key to these studies is very high-precision, high-resolution spectroscopy which can be carried out on much fainter stars, galaxies and quasars than is possible with the present generation of telescopes."

-Dr. Malcolm S. Longair, Chair of the Gemini Board 1994-1995

What is the chemical enrichment history of the Galaxy and the Universe? High resolution spectroscopy of the oldest stars in the Milky Way and of gas clouds illuminated by distant quasars when the Universe was less than one quarter its present age will enable us to determine how the abundances of elements heavier than hydrogen and helium were built up over time.

This program requires high-resolution spectroscopy of faint objects, which in turn requires excellent imaging at optical wavelengths, high throughput in the ultraviolet down to the atmospheric limit of transmission, and the large light-gathering power of Gemini's 8-m mirrors.

Image Credits: 1:KPNO

Ruth A. Kneale / / February 27, 1998