NASA's Hubble Reveals Thousands of Orion Nebula Stars

WASHINGTON, Jan. 11 /PRNewswire/ -- In one of the most detailed
astronomical images ever produced, NASA's Hubble Space Telescope
captured an unprecedented look at the Orion Nebula. This turbulent
star formation region is one of astronomy's most dramatic and
photogenic celestial objects.

"Orion is a bustling cauldron of activity. This new large-scale Hubble
image of the region reveals a treasure-house of beauty and astonishing
detail for comprehensive scientific study," said Jennifer Wiseman,
NASA's Hubble program scientist.

The crisp image is a tapestry of star formation. It varies from jets
fired by stars still embedded in their dust and gas cocoons to disks
of material encircling young stars that could be the building blocks
of future solar systems.

In a mosaic containing a billion pixels, Hubble's Advanced Camera for
Surveys uncovered thousands of stars never seen before in visible
light. Some are merely one-hundredth the brightness of previously
viewed Orion stars.

Among the stars Hubble spotted for the first time in visible light in
Orion were young brown dwarfs and a small population of possible
binary brown dwarfs (two brown dwarfs orbiting each other). Brown
dwarfs are so-called "failed stars." These cool objects are too small
to be ordinary stars, because they cannot sustain nuclear fusion in
their cores the way the sun does. Comparing the characteristics of
newborn stars and brown dwarfs in their natal environment provides
unique information about how they form.

"The wealth of information in this Hubble survey, including seeing
stars of all sizes in one dense place, provides an extraordinary
opportunity to study star formation," said observation leader Massimo
Robberto of the Space Telescope Science Institute, Baltimore. "Our
goal is to calculate the masses and ages for these young stars, so
that we can map their history and get a general scenario of the star
formation in that region. We can then sort the stars by mass and age
and look for trends."

Orion is a perfect laboratory to study how stars are born, because it
is 1,500 light-years away, a relatively short distance within our
100,000 light- year wide galaxy. Astronomers have a clear view into
this crowded stellar maternity ward, because massive stars in the
center of the nebula have blown out most of the dust and gas in which
they formed, carving out a cavity in the dark cloud of gas and dust.

"In this bowl of stars we see the entire formation history of Orion
printed into the features of the nebula: arcs, blobs, pillars, and
rings of dust that resemble cigar smoke," Robberto said. "Each one
tells a story of stellar winds from young stars that impact the
environment and the material ejected from other stars. This appears to
be a typical star-forming environment. Our sun may have been born 4.5
billion years ago in a cloud like this one."

This extensive study took 105 Hubble orbits to complete. All imaging
instruments aboard the telescope were used simultaneously to study
Orion. The Advanced Camera mosaic covers approximately the apparent
angular size of the full moon.

The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency. The Space Telescope
Science Institute conducts Hubble science operations. The Institute is
operated for NASA by the Association of Universities for Research in
Astronomy, Inc., Washington.

Robberto presented the findings today at the 207th meeting of the
American Astronomical Society in Washington. For images and
information about this research on the Web, visit:

http://hubblesite.org/news/2006/01 SOURCE NASA