Cool Cosmos: Orbiting telescope views infrared universe

Astronomers this week unveiled some really cool images–along with some positively chilling spectra. The new images include pictures of a hidden stellar nursery and the first spectra ever taken of organic material in a remote galaxy. An infrared observatory, the Spitzer Space Telescope, had gathered the data since its launch last August.

SEEING (INFRA)RED. False-color, infrared view of a glowing stellar nursery in the Elephant’s Trunk nebula. W. Reach/NASA/JPL
Inner (yellow-green) and outer (orange) parts of a debris disk surround the nearby star Fomalhaut. Stapelfeldt/NASA/JPL

The telescope “will change the way astronomers do astronomy,” predicts John N. Bahcall of the Institute for Advanced Study in Princeton, N.J. With Spitzer’s infrared capability, “it will no longer be astronomically correct to characterize a system by only X-ray, optical, or ultraviolet light,” he adds.

Previously known as the Space Infrared Telescope Facility and now renamed in honor of the late astronomer Lyman Spitzer Jr., the telescope records infrared radiation from some of the coldest, remotest and most-dust-obscured objects in the universe. It does so with higher resolution and greater sensitivity than any other infrared telescope sent into orbit, notes Spitzer project scientist Michael W. Werner of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. At a NASA press briefing, he and several of his colleagues presented images and spectra from Spitzer’s first few months of operation.

Peering at a brilliant but dust-shrouded galaxy more than 3 billion light-years from Earth, Spitzer detected an abundance of organic compounds, including frozen carbon monoxide, carbon dioxide, water, methane, and polycyclic aromatic hydrocarbons. The telescope recorded the organic compounds in the galaxy as it appeared 3.25 billion years ago, a time when primitive life had just gained a foothold on Earth.

The new finding suggests that “the building blocks [of life] are spread around the universe,” says Spitzer astronomer James R. Houck of Cornell University.

Looking closer to home, Spitzer has taken the first infrared image of a disk of dusty debris surrounding the bright star Fomalhaut, which is 25 light-years from Earth. Debris disks represent the spray of material generated by the collision of asteroids or comets, dust-rich leftovers from the planet-making process. Although telescopes that detect longer, submillimeter wavelengths already have imaged the outer part of Fomalhaut’s disk (SN: 4/25/98, p. 260: http://www.sciencenews.org/sn_arc98/4_25_98/fob1.htm), Spitzer is the first observatory to provide a full picture of the disk, says Karl R. Stapelfeldt of JPL.

The disk’s outer region, which has a radius of about 150 times the Earth-sun distance, roughly corresponds to the relative location of a reservoir of comets near our solar system’s edge. The newly imaged inner region of the disk comes as close to Fomalhaut as Saturn does to the sun and may mark the location of an inner asteroid belt circling the star, notes Stapelfeldt.

Spitzer found that one section of the outer part of Fomalhaut’s disk was noticeably brighter than the other and so has a higher dust concentration. The gravitational influence of an unseen planet could be responsible, notes Stapelfeldt.

Elsewhere in the Milky Way, Spitzer viewed a dark, elongated globule known as the Elephant’s Trunk nebula. The infrared images reveal several embryonic stars as well as young but fully formed stars. In visible light, these stars are hidden by dust and dense gas.

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