Galaxy Exposes Its Dusty Inner Workings in New Spitzer Image

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NEWS RELEASE: 2010-003 Jan. 5, 2010

Galaxy Exposes Its Dusty Inner Workings in New Spitzer Image

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-003&cid=release_2010-003

NASA's Spitzer Space Telescope has captured an action-packed picture of the nearby
Small Magellanic Cloud, a small galaxy that looks like a wispy cloud when seen from
Earth.

From Spitzer's perch up in space, the galaxy's clouds of dust and stars come into clear
view. The telescope's infrared vision reveals choppy piles of recycled stardust -- dust that
is being soaked up by new star systems and blown out by old ones.

To some people, the new view might resemble a sea creature, or even a Rorschach inkblot
test. But to astronomers, it offers a unique opportunity to study the whole life cycle of
stars close-up. The image is available online at http://www.nasa.gov/AAS and
http://www.jpl.nasa.gov/aas .

"It's quite the treasure trove," said Karl Gordon, the principal investigator of the latest
Spitzer observations at the Space Telescope Science Institute in Baltimore, Md. "Because
this galaxy is so close and relatively large, we can study all the various stages and facets
of how stars form in one environment."

The Small Magellanic Cloud, and its larger sister galaxy, the Large Magellanic Cloud, are
named after the seafaring explorer Ferdinand Magellan, who documented them while
circling the globe nearly 500 years ago. From Earth's southern hemisphere, they can
appear as wispy clouds. The Small Magellanic Cloud is the farther of the pair, at 200,000
light-years away.

Recent research has shown that the galaxies may not, as previously suspected, orbit
around the Milky Way. Instead, they are thought to be merely sailing by, destined to go
their own way. Astronomers say the two galaxies, which are both less evolved than a
galaxy like ours, were triggered to create bursts of new stars by gravitational interactions
with the Milky Way and with each other. In fact, the Large Magellanic Cloud may
eventually consume its smaller companion.

Gordon and his team are interested in the Small Magellanic Cloud not only because it is
so close and compact, but also because it is very similar to young galaxies thought to
populate the universe billions of years ago. The Small Magellanic Cloud has only one-fifth
the amount of heavier elements, such as carbon, contained in the Milky Way, which
means that its stars haven't been around long enough to pump large amounts of these
elements back into their environment. Such elements were necessary for life to form in
our solar system.

Studies of the Small Magellanic Cloud therefore offer a glimpse into the different types
of environments in which stars form.

The new Spitzer observations were presented today at the 215th meeting of the American
Astronomical Society in Washington. They reveal the galaxy's youngest stars embedded
in thick dust, in addition to the older stars, which spit the dust out. Taken together with
visible-light observations, these Spitzer data help provide a census of the whole stellar
population.

"With Spitzer, we are pinpointing how to best calculate the numbers of new stars that are
forming right now," said Gordon. "Observations in the infrared give us a view into the
birthplace of stars, unveiling the dust-enshrouded locations where stars have just formed."

Infrared light is color-coded in the new picture, so that blue shows older stars, green
shows organic dust and red highlights dust-enshrouded star formation. Light encoded in
blue has a wavelength of 3.6 microns; green is 8.0 microns; and red is 24 microns. This
image was taken before Spitzer ran out of its liquid coolant in May 2009 and began its
"warm" mission.

Other collaborators include: M. Meixner, M, Sewilo and B. Shiao of the Space Telescope
Science Institute; M. Meade, B. Babler, S. Bracker of the University of Wisconsin at
Madison; C. Engelbracht, M. Block, K. Misselt of the University of Arizona, Tucson; R.
Indebetouw of the University of Virginia, Charlottesville; and J. Hora and T. Robitaille
of the Harvard Smithsonian Center for Astrophysics, Cambridge, Mass.

The image includes Spitzer observations taken previously by a team led by Alberto
Bolatto of the University of Maryland, College Park.

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 at the California Institute of
Technology in Pasadena. Caltech manages JPL for NASA.

For more information about Spitzer, visit http://www.spitzer.caltech.edu/spitzer and
http://www.nasa.gov/spitzer .

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