Spitzer image of a disc of planet-forming debris encircling the nearby star called Fomalhaut.

(PLANETQUEST) -- NASA's new orbiting observatory, the Spitzer Space Telescope, has obtained the first infrared images of the massive dust disc surrounding the nearby star Fomalhaut.

Such debris discs are the leftover material from the building of a planetary system. While other telescopes have imaged the outer Fomalhaut disc, none was able to provide a full picture of the inner region. Spitzer's ability to detect dust at various temperatures allows it to fill in this missing gap, providing astronomers with insight into the evolution of planetary systems.

The Spitzer Space Telescope, launched August 25, is the fourth of NASA's Great Observatories, a program designed to paint a more comprehensive picture of the cosmos using different wavelengths of light.

While the other Great Observatories have probed the universe with visible light (Hubble Space Telescope), gamma rays (Compton Gamma Ray Observatory) and X-rays (Chandra X-ray Observatory), the Spitzer Space Telescope observes the cosmos in the infrared.

Artist's concept of the Spitzer Space Telescope

Formerly known as the Space Infrared Telescope Facility, the spacecraft was officially named today after the late Dr. Lyman Spitzer, Jr., one of the 20th century's most influential scientists. In the mid-1940s, he first proposed placing telescopes in space.

Planets are believed to form from a flattened disc-like cloud of gas and dust orbiting a star very early in its life. The Spitzer telescope was designed in part to study these circumstellar discs, where the dust particles are so cold that they radiate primarily at infrared wavelengths. Located in the constellation Piscis Austrinus, Fomalhaut and its putative planetary system are located of 25 light-years away.

Twenty years ago, the Infrared Astronomical Satellite, the first orbiting infrared telescope, detected much more infrared radiation coming from Fomalhaut than was expected for a normal star of this type. The dust is presumed to be debris left over from the formation of a planetary system. However, the satellite did not have adequate spatial resolution to image the dust directly.

Subsequent measurements with sub-millimeter radio telescopes suggested that Fomalhaut is surrounded by a huge dust ring 370 astronomical units (an astronomical unit is the average distance between the Sun and Earth), or 34 billion miles (56 billion kilometers) in diameter. This corresponds to a size of nearly five times larger than our own solar system.