From the National Optical Astronomical Observatories
This image of M51 the constellation of Canes Venatici was made by combining three CCD frames, taken at the Kitt Peak 0.9m telescope in 1991. By using different filters in front of the monochrome detector, corresponding approximately to the primary colors red, green and blue, one can recreate a true color picture. Orientation: N to the left, E down. Distance: approximately 19 million light years. Size: over 65000 light years across.
M51 (NGC 5194/5195, Arp 85, VV 1) comprises the large spiral galaxy NGC 5194 and its smaller, barred and more amorphous companion NGC 5195. NGC 5195's reddish tinge due that it is behind the dust-filled arm connecting it to NGC 5194. The spiral arms are perhaps the most perfect `textbook' example in any nearby galaxy, and their very perfection points to the presence of a long-lasting confining mechanism. This may be provided by the tidal pull of NGC 5195, whose gravitational effects can generate the necessary spiral density waves. This pattern also shows up in radio emission, suggesting that the magnetic fields in the Whirlpool are also compressed by the density wave. The innermost core of NGC 5194 contains a bright ultraviolet source, as well as one of the brightest known compact radio sources. Although smaller and less massive than our own Galaxy, M51 is considerably brighter, due to recent star formation and the resultant dominance by young, hot, bright stars of types O and B.
Image Title: M51, the Whirlpool Nebula, NGC 5194/5195
Credit: Todd Boroson/AURA/NOAO/NSF
The text is based on accompanying on-line materials.
Last Modified On: Sunday, December 17, 2000