NASA'S Neowise Completes Scan For Asteroids And Comets

NEOWISE is an enhancement of the Wide-field Infrared Survey Explorer,
or WISE, mission that launched in December 2009. WISE scanned the
entire celestial sky in infrared light about 1.5 times. It captured
more than 2.7 million images of objects in space, ranging from
faraway galaxies to asteroids and comets close to Earth.

In early October 2010, after completing its prime science mission, the
spacecraft ran out of frozen coolant that keeps its instrumentation
cold. However, two of its four infrared cameras remained operational.
These two channels were still useful for asteroid hunting, so NASA
extended the NEOWISE portion of the WISE mission by four months, with
the primary purpose of hunting for more asteroids and comets, and to
finish one complete scan of the main asteroid belt.

"Even just one year of observations from the NEOWISE project has
significantly increased our catalog of data on NEOs and the other
small bodies of the solar systems," said Lindley Johnson, NASA's
program executive for the NEO Observation Program.

Now that NEOWISE has successfully completed a full sweep of the main
asteroid belt, the WISE spacecraft will go into hibernation mode and
remain in polar orbit around the Earth, where it could be called back
into service in the future.

In addition to discovering new asteroids and comets, NEOWISE also
confirmed the presence of objects in the main belt that already had
been detected. In just one year, it observed about 153,000 rocky
bodies out of approximately 500,000 known objects. Those include the
33,000 that NEOWISE discovered.

NEOWISE also observed known objects closer and farther to us than the
main belt, including roughly 2,000 asteroids that orbit along with
Jupiter, hundreds of NEOs and more than 100 comets.

These observations will be key to determining the objects' sizes and
compositions. Visible-light data alone reveals how much sunlight
reflects off an asteroid, whereas infrared data is much more directly
related to the object's size. By combining visible and infrared
measurements, astronomers also can learn about the compositions of
the rocky bodies -- for example, whether they are solid or crumbly.
The findings will lead to a much-improved picture of the various
asteroid populations.

NEOWISE took longer to survey the whole asteroid belt than WISE took
to scan the entire sky because most of the asteroids are moving in
the same direction around the sun as the spacecraft moves while it
orbits the Earth. The spacecraft field of view had to catch up to,
and lap, the movement of the asteroids in order to see them all.

"You can think of Earth and the asteroids as racehorses moving along
in a track," said Amy Mainzer, the principal investigator of NEOWISE
at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We're moving
along together around the sun, but the main belt asteroids are like
horses on the outer part of the track. They take longer to orbit than
us, so we eventually lap them."

NEOWISE data on the asteroid and comet orbits are catalogued at the
NASA-funded International Astronomical Union's Minor Planet Center, a
clearinghouse for information about all solar system bodies at the
Smithsonian Astrophysical Observatory in Cambridge, Mass. The science
team is analyzing the infrared observations now and will publish new
findings in the coming months.

When combined with WISE observations, NEOWISE data will aid in the
discovery of the closest dim stars, called brown dwarfs. These
observations have the potential to reveal a brown dwarf even closer
to us than our closest known star, Proxima Centauri, if such an
object does exist. Likewise, if there is a hidden gas-giant planet in
the outer reaches of our solar system, data from WISE and NEO-WISE
could detect it.

The first batch of observations from the WISE mission will be
available to the public and astronomical community in April.
"WISE has unearthed a mother lode of amazing sources, and we're having
a great time figuring out their nature," said Edward (Ned) Wright,
the principal investigator of WISE at UCLA.

JPL manages WISE for NASA's Science Mission Directorate at the
agency's headquarters in Washington. The mission was competitively
selected under NASA's Explorers Program, which NASA's Goddard Space
Flight Center in Greenbelt, Md., manages. The Space Dynamics
Laboratory in Logan, Utah, built the science instrument, and Ball
Aerospace & Technologies Corp. of Boulder, Colo., built the
spacecraft. Science operations and data processing take place at the
Infrared Processing and Analysis Center at the California Institute
of Technology in Pasadena. JPL manages NEOWISE for NASA's Planetary
Sciences Division. The mission's data processing also takes place at
the Infrared Processing and Analysis Center.

For more information about WISE, visit:

http://www.nasa.gov/wise

Source: NASA

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