The Soap Bubble Nebula PN G75.5+1.7 (PM Ju 1) is a Planetary Nebula in constellation Cygnus. It was discovered in 2008 by amateur astronomer Dave Jurasevich on narrowband images he just took with a 160mm refractor. Later he also identified it on older photographs he had been taking during 2007.
The reason for this late discovery are the low brightness and contrast of the nebula, which also is located in front of a HII-region. This makes it hard to detect even in narrowband images. Furthermore, this circumstance complicates spectroscopic measurements, and yet there is still comparably rare information available.
The nebula extends about 4.3' x 3.9'. Assuming its location to be close to the 4000 LJ distant HII-region IC 1318, Jurasevic estimated its absolute diameter to roughly 5 LJ. Further assuming a typical expansion velocity of 35 km/s (cf. Abell 39, Helix Nebula) would result in the bubble's age of 22000 years.
See also
http://tinyurl.com/ku4ppyThe bright star in the lower right corner is P Cygni, a variable bright blue Hyper Giant of spectral type B2 Ia, and one of the brightest stars in the Milky Way. Its brightness only varies arount 4.5 ... 5.1 Mag today, but it did so much more in history.
Comments