Spitzer Unveils Infant Stars in the Christmas Tree Cluster

SPITZER UNVEILS INFANT STARS IN THE CHRISTMAS TREE CLUSTER
(From Lori Stiles, UA, University Communications, 520-621-1877)

- Thursday, December 22, 2005

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Contact Information
Erick T. Young 520-661-8520 (mobile)
520-621-4119 (office)

Related Web sites - URL for high-res image download
http://www.spitzer.caltech.edu/Media...ig05-028.shtml
http://www.cfa.harvard.edu/press/pr0540image.html
http://uanews.org/silk/request/051222_ngc2264.tif
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Astronomers using NASA's Spitzer Space Telescope have given the world a
spectacular new picture of a star-forming region called the "Christmas
Tree
Cluster," complete with first-ever views of a group of newborn stars
still
linked to their siblings.

Spitzer's cameras are very sensitive to the infrared (heat), allowing
astronomers to see through the obscuring gas and dust of the
star-forming
cloud that swaddles infant stars.

The Christmas Tree Cluster, also known as NGC 2264, is a well-studied
region in the Monoceros (the Unicorn) constellation. The Christmas Tree
Cluster was so named because it looks like a tree in visible light. The
nebula is roughly 2,500 light-years away. That is, the nebula emitted
the
light in the new Spitzer image 2,500 years ago.

For astronomers studying the development of very young stars -- stars
less
than a few million years old -- "This region has it all," said
University of
Arizona astronomer Erick T. Young.

"We see the dramatic-looking emission of cold gas -- clouds that look
like
thunderheads. We see when the massive molecular cloud breaks up and
begins
to condense into clumps of stars," Young said. "And, for the first
time,
because of Spitzer's sensitivity, we can see individual stars roughly
the
size of our sun tightly packed within those clumps." The cluster of
stars is
so tightly packed that they must be less than 100,000 years old, he
added.

Astronomers are calling this compact collection of bright protostars
within
the Christmas Tree Cluster the "Snowflake Cluster" because of how they
are
spaced. The newborn stars are patterned like a single feathery crystal
of
snow, or geometrically spaced like spokes in a wheel.

The Spitzer observations show that just as theory predicts, the density
and
temperature of the initial star-forming cloud dictates the spacing
between
the protostars.

Young is deputy principal investigator for Spitzer's Multiband Imaging
Photometer (MIPS), a UA-built camera that took the longest wavelengths
of
infrared light used in Christmas Tree Cluster mosaic. Astronomers
combined
light from MIPS and Spitzer's Infrared Array Camera (IRAC), developed
by the
Smithsonian Astrophysical Observatory, in constructing in the picture.

High-resolution Spitzer images of the Christmas Tree Cluster are online
at
http://www.spitzer.caltech.edu/Media...ig05-028.shtml,
http://www.cfa.Harvard.edu/press/pr0540image.html and
http://uanews.org/silk/request/051222_ngc2264.tif

The infant stars appear as pink and red specks in the snowflake cluster
that adorns the larger Christmas Tree Cluster in the IRAC and MIPS
image.
The larger, yellowish spheres are massive stars within the NGC 2264
region.
The organic molecules mixed in with dust that surrounds the cluster are
illuminated as wisps of green. The blue dots smeared across the image
are
older Milky Way stars at various distances along the telescope's line
of
sight.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer
mission for NASA's Science Mission Directorate. Science operations are
conducted at the Spitzer Science Center at the California Institute of
Technology in Pasadena. JPL is a division of Caltech.