Giant Starbirth Region In Neighboring Galaxy
This is a Hubble Space Telescope image of a vast nebula called NGC 604, which lies in the
neighboring spiral galaxy M33, located 2.7 million light-years away in the constellation
This is a site where new stars are being born in a spiral arm of the galaxy. Though such nebulae
are common in galaxies, this one is particularly large, nearly 1,500 light-years across. The
nebula is so vast it is easily seen in ground-based telescopic images.
At the heart of NGC 604 are over 200 hot stars, much more massive than our Sun (15 to 60 solar
masses). They heat the gaseous walls of the nebula making the gas fluoresce. Their light also
highlights the nebula's three-dimensional shape, like a lantern in a cavern. By studying the
physical structure of a giant nebula, astronomers may determine how clusters of massive stars
affect the evolution of the interstellar medium of the galaxy. The nebula also yields clues to
its star formation history and will improve understanding of the starburst process when a galaxy
undergoes a "firestorm" of star formation.
The image was taken on January 17, 1995 with Hubble's Wide Field and Planetary Camera 2.
Separate exposures were taken in different colors of light to study the physical properties of
the hot gas (17,000 degrees Fahrenheit, 10,000 degrees Kelvin).
Credit: Hui Yang (University of Illinois) and NASA