NGC 604 in M33 -

Giant diffuse nebula and star forming region NGC 604 in M33

This is a Hubble Space Telescope image (right) of a vast nebula

NGC 604 in the Triangulum galaxy M33.

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 (left).

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 flouresce. 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).

Credits: Hui Yang (University of Illinois),

Jeff J. Hester (Arizona State University), and NASA.

This image is also available as

~740k b/w hi-res jpeg

Last Modification: 18 Apr 1998, 20:35 MET