Raw Ingredients for Life Detected in Planetary Construction Zones
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.
These materials, icy dust particles coated with water, methanol and
carbon dioxide, may help explain the origin of icy planetoids like
comets. Scientists believe these comets may have endowed Earth with
some of its water and many of its biogenic, life-enabling materials.
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.
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Artist's concept of icy dust
particles. A related animation zooms in on a planet-forming disc
around an infant star to reveal the dust particles that make up
the disc. NASA's Spitzer Space Telescope detected the raw ingredients
for planets and ultimately life in these dust particles.
Animation:
RealVideo
or QuickTime |
| |
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 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 , Pasadena, Calif.,
which manages the mission.
Spitzer also discovered two of the farthest and faintest planet-
forming discs ever observed. These discs surround two of more than
300 newborn stars uncovered for the first time in a stunning new
image of the dusty stellar nursery called RCW 49. It is
approximately 13,700 light-years from Earth in the constellation
Centaurus.
"Preliminary data suggest that 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, or "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 issue of the
journal Astrophysical Journal Supplements. For images and
information about the research on the Internet, visit:
http://www.spitzer.caltech.edu/ and http://photojournal.jpl.nasa.gov
.
JPL manages the Spitzer Space Telescope mission for NASA's Office of
Space Science, Washington. Science operations are conducted at the
Spitzer Science Center at the California Institute of Technology,
Pasadena, Calif. JPL is a division of Caltech. Spitzer's infrared
spectrograph was built by Cornell University, Ithaca, N.Y., and Ball
Aerospace Corporation, Boulder, Colo. The instrumentÂ’s development
was led by Dr. Jim Houck of Cornell. Spitzer's infrared array camera
was built by NASA Goddard Space Flight Center, Greenbelt, Md. The
camera's development was led by Dr. Giovanni Fazio of Smithsonian
Astrophysical Observatory, Cambridge, Mass.
