NGC 4725

Distance: 41 million Light Years

Consetllation: Coma Berenices

Right Ascension: 12 : 50.4 (hours : minutes)
Declination: +25 : 30 (degrees : minutes)

NGC 4725 is a member of the Coma II subgroup of galaxies within the larger Coma-Sculptor grouping. A ringlike zone of HII regions and active star formation places NGC 4725 in a distinct morphological subgroup of galaxies called "Ringed galaxies". Rings or pseudorings make up about 50% of all early to intermediate Hubble type galaxies. Ringlike patterns are believed to occur when a galaxy's internal dynamics are altered by symmetry disturbances especially the presence of a bar or an asymmetric density wave. The result is a phenomenon called "orbital resonances" which is believed to lead to the formation of ringlike structures. The presence of a central bar along the long axis of the inner ring of NGC 4725 supports this theory. Observed properties of rings include their preference for noncircular shapes and their tendency to be aligned either parallel or perpendicular to bars. The rings are almost always zones of heightened star formation. Double ring systems exist as well, M94 being a fine example. The multiple rings tend to have preferred ratios regarding their radius and galactocentric distances. In the image the small appearing spiral in the lower right is an unrelated background galaxy located approximately 200 million years away.