Raw ingredients for life detected around young stars
NASA NEWS RELEASE
Posted: May 27, 2004
NASA has announced new findings from the Spitzer Space Telescope, including the discovery of significant amounts of icy organic materials sprinkled throughout several "planetary construction zones," or dusty planet-forming discs, which circle infant stars.
Drs. Dan Watson and William Forrest of the University of Rochester, N.Y, identified the ices. They surveyed five very young stars in the constellation Taurus, 420 light-years from Earth. Previous studies identified similar organic materials in space, but this is the first time they were seen unambiguously in the dust making up planet-forming discs.
In another finding, Spitzer surveyed a group of young stars and found intriguing evidence that one of them may have the youngest planet detected. The observatory found a clearing in the disc around the star CoKu Tau 4. This might indicate an orbiting planet swept away the disc material, like a vacuum leaving a cleared trail on a dirty carpet. The new findings reveal the structure of the gap more clearly than ever before. Because CoKu Tau 4 is only about one million years old, the possible planet would be even younger. As a comparison, Earth is approximately 4.5-billion years old.
"These early results show Spitzer will dramatically expand our understanding of how stars and planets form, which ultimately helps us understand our origins," said Dr. Michael Werner, Spitzer project scientist at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., which manages the mission.
"Preliminary data suggest all 300 or more stars harbor discs, but so far we've only looked closely at two. Both were found to have discs," said Dr. Ed Churchwell of the University of Wisconsin, Madison, Wis., principal investigator of the RCW 49 research, with Dr. Barbara Whitney of Space Science Institute, Boulder, Colo.
Planet forming, "protoplanetary," discs are a natural phase in a star's life. A star is born inside a dense envelope of gas and dust. Within this envelope, and circling the star, is a flat, dusty disc, where planets are born.
"By seeing what's behind the dust, Spitzer has shown us star and planet formation is a very active process in our galaxy," Churchwell said.
Spitzer's exquisitely sensitive infrared eyes can see planet forming discs in great detail. "Previously, scientists could study only a small sample of discs, but Spitzer is already on its way toward analyzing thousands of discs," Werner said.
Spitzer's infrared spectrograph instrument, which breaks apart infrared light to see the signatures of various chemicals, was used to observe the organic ices and the clearing within CoKu Tau 4's disc. Spitzer's infrared array camera found the new stars in RCW 49. Papers on the research will appear in the September 1, 2004, issue of the journal Astrophysical Journal Supplements.