Press Release

Firestorm of Star Birth Seen in Local Galaxy

By SpaceRef Editor
December 4, 2003
Filed under , ,
Firestorm of Star Birth Seen in Local Galaxy
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This festively colorful nebula, called NGC 604, is one of the
largest known seething cauldrons of star birth in a nearby
galaxy. NGC 604 is similar to familiar star-birth regions in
our Milky Way galaxy, such as the Orion Nebula, but it is vastly
larger in extent and contains many more recently formed stars.

This monstrous star-birth region contains more than 200 brilliant
blue stars within a cloud of glowing gases some 1,300 light-years
across, nearly 100 times the size of the Orion Nebula. By contrast,
the Orion Nebula contains just four bright central stars. The
bright stars in NGC 604 are extremely young by astronomical
standards, having formed a mere 3 million years ago.

Most of the brightest and hottest stars form a loose cluster
located within a cavity near the center of the nebula. Stellar
winds from these hot blue stars, along with supernova explosions,
are responsible for carving out the hole at the center. The most
massive stars in NGC 604 exceed 120 times the mass of our Sun,
and their surface temperatures are as hot as 72,000 degrees
Fahrenheit (40,000 Kelvin). Ultraviolet radiation floods out from
these hot stars, making the surrounding nebular gas fluoresce.

NGC 604 lies in a spiral arm of the nearby galaxy M33, located
about 2.7 million light-years away in the direction of the
constellation Triangulum. M33, a member of the Local Group of
galaxies that also includes the Milky Way and the Andromeda
Galaxy, can be seen easily with binoculars. NGC 604 itself
can be seen in a small telescope, and was first noted by the
English astronomer William Herschel in 1784. Within our Local
Group, only the Tarantula Nebula in the Large Magellanic Cloud
exceeds NGC 604 in the number of young stars, even though the
Tarantula Nebula is slightly smaller in size.

NGC 604 provides Hubble astronomers with a nearby example of a
giant star-birth region. Such regions are small-scale versions
of more distant “starburst” galaxies, which undergo an extremely
high rate of star formation. Such starbursts are believed to have
been common in the early universe, when the star-formation rate
was much higher. Supernovae exploding in these galaxies created
the first chemical elements heavier than hydrogen and helium.

The image of NGC 604 was assembled from observations taken with
Hubble’s Wide Field Planetary Camera 2 in 1994, 1995, and 2001.
Color filters were used to isolate light emitted by hydrogen,
oxygen, nitrogen, and sulfur atoms in the nebula and ultraviolet,
visible and infrared light from the stars within NGC 604 and the
nearby spiral arms of M33. Image processors from the Hubble
Heritage team at the Space Telescope Science Institute combined
these various filter images to create this color picture.

Image Credit: NASA and The Hubble Heritage Team (AURA/STScI)
Acknowledgment: D. Garnett (U. Arizona), J. Hester (ASU), and
J. Westphal (Caltech)

NOTE TO EDITORS: For additional information, please contact
Keith Noll, Hubble Heritage Team, Space Telescope Science
Institute, 3700 San Martin Drive, Baltimore, MD 21218, (phone)
410-338-1828, (fax) 410-338-4579, (e-mail) noll@stsci.edu or

Howard Bond, Hubble Heritage Team, Space Telescope Science
Institute, 3700 San Martin Drive, Baltimore, MD 21218, (phone)
410-338-4718, (fax) 410-338-4579, (e-mail) bond@stsci.edu

Electronic images and additional information are available at

The Space Telescope Science Institute (STScI) is operated by the
Association of Universities for Research in Astronomy, Inc. (AURA),
for NASA, under contract with the Goddard Space Flight Center,
Greenbelt, MD. The Hubble Space Telescope is a project of
international cooperation between NASA and the European Space
Agency (ESA).

SpaceRef staff editor.