Jet Propulsion Laboratory, Pasadena, Calif.
Image Advisory: 2006-099 August 14, 2006
NASA'S Spitzer Digs Up Troves of Possible Solar Systems in Orion
Astronomers have long scrutinized the vast and layered clouds of the
Orion nebula, an
industrious star-making factory visible to the naked eye in the sword
of the famous hunter
constellation. Yet, Orion is still full of secrets.
A new image from NASA's Spitzer Space Telescope probes deep into the
clouds of dust
that permeate the nebula and its surrounding regions. The striking
false-color picture
shows pinkish swirls of dust speckled with stars, some of which are
orbited by disks of
planet-forming dust.
The image can be seen by visiting:
www.spitzer.caltech.edu/Media/releases/s...16/ssc2006-16a.shtml
.
Spitzer, with its powerful infrared vision, was able to unearth nearly
2,300 such planet-
forming disks in the Orion cloud complex, a collection of turbulent
star-forming clouds
that includes the well-known Orion nebula.
The disks - made of gas and dust that whirl around young suns - are too
small and distant
to be seen by visible-light telescopes; however, the infrared glow of
their warm dust is
easily spotted by Spitzer's infrared detectors. Each disk has the
potential to form planets
and its own solar system.
"This is the most complete census of young stars with disks in the
Orion cloud complex,"
said Dr. Thomas Megeath of the University of Toledo, Ohio, who led the
research.
"Basically, we have a census of potential solar systems, and we want to
know how many
are born in the cities, how many in small towns, and how many out in
the countryside."
A look at Orion's demographics reveals that the potential solar systems
populate a variety
of environments. Megeath and his colleagues found that about 60 percent
of the disk-
sporting stars in the Orion cloud complex inhabit its bustling
"cities," or clusters,
containing hundreds of young stars. About 15 percent reside in small
outer communities,
and a surprising 25 percent prefer to go it alone, living in isolation.
Prior to the Spitzer observations, scientists thought that up to 90
percent of young stars,
both with and without disks, dwelled in cities like those of Orion.
"The Orion image shows that many stars also appear to form in isolation
or in groups of
just a few stars," said team member Dr. John Stauffer of NASA's Spitzer
Science Center
at the California Institute of Technology in Pasadena. "These new data
may help us to
determine the type of environment in which our sun formed."
Astronomers do not know whether our middle-aged sun grew up in the
stellar equivalent
of the city or countryside, though most favor a large city scenario.
Newborn stars like the
ones in Orion tend to drift away from their siblings over time, so it
is hard to trace an
adult star's origins.
Megeath and his colleagues estimate that about 60 to 70 percent of the
stars in the Orion
cloud complex have disks. "It is an interesting question why this
number isn't 100
percent. Eventually, we may be able to understand why some stars don't
have disks,"
said Megeath.
Spitzer's infrared vision also dug up 200 stellar embryos in the Orion
cloud complex,
most of which had never been seen before. Stellar embryos are still too
young to have
developed disks.
The Orion cloud complex is about 1,450 light-years from Earth and spans
about 240
light-years of space. Spitzer's wide field of view allowed it to survey
most of the
complex, an area of the sky equivalent to 28 full moons. The featured
image shows a
slice of this survey, the equivalent of four full moons-worth of sky,
and includes the
Orion nebula itself.
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer
Space
Telescope mission for NASA's Science Mission Directorate, Washington.
Science
operations are conducted at the Spitzer Science Center. Caltech manages
JPL for NASA.
Spitzer's infrared array camera, which made the observations, was built
by NASA's
Goddard Space Flight Center, Greenbelt, Md. The instrument's principal
investigator is
Dr. Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics.
For more Orion graphics and information, visit:
www.spitzer.caltech.edu/spitzer
.
-end-
Deirdre Kelleghan
Irish Astronomical Society
www.irishastrosoc.org
  