Spitzer Harvests Dozens of New Stars (Forwarded)

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For Release: Tuesday, November 15, 2005

Release No.: 05-36

Spitzer Harvests Dozens of New Stars

Cambridge, MA -- Just in time for Thanksgiving, NASA's Spitzer Space
Telescope has harvested a bounty of young stars. A new infrared image of
the reflection nebula NGC 1333, located about 1,000 light-years from
Earth in the constellation Perseus, reveals dozens of stars like the Sun
but much younger.

"These newborns are less than a million years old -- babies by
astronomical standards," said Rob Gutermuth of the Harvard-Smithsonian
Center for Astrophysics (CfA). "Our Sun may have formed in a similar
environment 4.5 billion years ago."

Most of the visible light from the region's young stars is obscured by
the dusty cloud in which they formed. With Spitzer, astronomers can
detect infrared light from these objects, allowing them to peer through
the dust and gain a more detailed understanding of how stars like our
Sun are born.

Spitzer's infrared view of NGC 1333 uncovered streaks and splotches of
nebulosity that appear green in this color-coded image. These features
are glowing shock fronts where jets of material spewed from the youngest
protostars have rammed into the cold natal gas cloud. By stirring up the
cold gas, these jets may eventually clear away the gas, shutting down
future star formation.

"The sheer number of separate jets that appear in this region is
unprecedented," said Alicia Porras of CfA. "Sorting through them and
untangling them will prove quite a challenge as we try to identify which
protostar is the source of each jet."

In contrast, the upper portion of NGC 1333 is dominated by infrared
light from warm dust, shown as red in this image. In this area, young
stars have already dispersed the surrounding material, opening up a
cavity in the side of the cloud. Ultraviolet light from the more massive
stars located there is heating the dust along the edge of the cavity and
causing it to glow.

In addition to the nebulosity, detailed analysis of the infrared light
from the young stars in NGC 1333 reveals that about 80 are surrounded by
discs of dusty material where new planets may be forming. The entire
group of objects spans only 4 light-years. In contrast, only one star
system (containing three stars) lies within 4 light-years of the Sun.

"If our solar system were located inside NGC 1333, our night sky would
look very different," said Gutermuth. "We would see fewer stars since
any distant stars would be hidden by the nearby dust. We would need an
instrument like Spitzer to see out of the nebula."

The newborn stars within NGC 1333 don't reside in a single cluster, but
instead are split between two sub-groups: one group to the north, near
the red nebulosity, and the other to the south, near the green shocks.

"With the sharp infrared eyes of Spitzer, we can look for differences
between these two groups of stars," said Porras. "The results could
reveal hints of the star-forming history of this region."

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. NASA's Goddard Space Flight Center built
Spitzer's Infrared Array Camera, which took the observations. The
instrument's principal investigator is Giovanni Fazio of CfA.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for
Astrophysics (CfA) is a joint collaboration between the Smithsonian
Astrophysical Observatory and the Harvard College Observatory. CfA
scientists, organized into six research divisions, study the origin,
evolution and ultimate fate of the universe.

Note to editors:
High-resolution images to accompany this release are online at
http://www.cfa.harvard.edu/press/pr0536image.html