M 27, also called the Dumbbell Nebula (NGC 6853) is
found in the constellation Vulpecula and was the first
planetary nebula ever discovered. Charles Messier was
the first to observe it on July 12, 1764. It has a
magnitude of 7.4, and can be seen under good conditions
with a pair of 10x50 binoculars. The bright portion of
the nebula is apparently expanding at a rate of 6.8
arc seconds per year, and has an estimated observable
age of 3000 to 4000 years (it actually happened earlier
as the light had to travel the approximate distance of
1000 light years*). The central star of M27 is quite
bright at a magnitude of 13.5, and is an extremely hot
bluish dwarf star at about 85,000 Kelvins. K.M.
Cudworth of the Yerkes Observatory found that it
probably has a faint (magnitude 17) yellow companion
star. *Hubble is now investigating M27 to determine
a more accurate distance.
--Barbara and Joran Kreiss