1 First Fruits of the Spitzer Space Telescope: Galactic and Solar System Studies Michael Werner,1 Giovanni Fazio,2 George Rieke,3 Thomas L. Roellig,4 and 5 Dan M. Watson 1Astronomy and Physics Directorate, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109; email:
[email protected] 2Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138; email:
[email protected] 3Steward Observatory, University of Arizona, Tucson, Arizona 85721; email:
[email protected] 4Astrophysics Branch, NASA/Ames Research Center, Moffett Field, California 94035; email:
[email protected] 5Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627; email:
[email protected] Key Words brown dwarfs, circumstellar disks, exoplanets, infrared astronomy, planetary system formation, space technology, star formation, stellar evolution ■ Abstract The Spitzer Space Telescope, launched in August 2003, is the infrared member of NASA’s Great Observatory family. Spitzer combines the intrinsic sensitivity of a cryogenic telescope in space with the imaging and spectroscopic power of modern infrared detector arrays. This review covers early results from Spitzer that have produced major advances in our understanding of our own solar system and phenomena within the Galaxy. Spitzer has made the first detection of light from extrasolar planets, characterized planet-forming and planetary debris disks around solar-type stars, showed that substellar objects with masses smaller than 10 MJup form through the same processes as do solar-mass stars, and studied in detail the composition of cometary ejecta in our Solar System. Spitzer’s major technical advances will pave the way for yet more powerful future instruments.