M-94, a bright spiral galaxy easily visible from Earth, is shown to have an active "ring of fire" in a new image released on May 16 by NASA and the Jet Propulsion Laboratories (JPL). This spiral galaxy lies 17 million light years away from Earth, seen in the Constellation Canes Venatici, Latin for "Hunting Dogs.".
The new photograph was recorded in infrared light, which is seen in the image in various colors. The red regions are the coolest and the blue regions are the hottest. The stellar nursery revealed by this new image from JPL is the coolest region, since the area is not as populated by as many stars as other parts of the galaxy. The energy given off by the young stars warms the surrounding gas (mostly hydrogen), causing it to glow in infrared light.
The red and yellow regions in the new image show a region that researchers are dubbing a "ring of fire." It is an area of tremendous star formation, where young stars first begin to fuse hydrogen into helium, igniting the nuclear furnaces.
The new photograph was recorded by the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope. Spitzer was launched in 2003 for a cost of $720 million dollars.
Extremely active regions of star formation such as this one are dubbed starburst rings by astronomers. Most commonly, starburst formations such as this are formed when one galaxy passes by another, altering the density of gases within the pair of star systems. In the case of M94, that region in this photograph may have been created by the oval shape of the galaxy itself.
The galaxy was first discovered in 1781 by Charles Messier, a comet-hunter who created one of the world's most widely-used catalogs of nebula and galaxies.
Until 2009, it was believed that M-94 showed two distinct rings - inner and outer structures, with the inner such ring being brighter and denser than the outlying system. A composite photo created that year showed that the two rings are part of a single larger structure. What appears to be the single, fainter outer band may consist of two spiral arms that make up part of the system.
