Planetary Nebula Humason 1-2
History
The planetary nebula Hu 1-2 (PN G086.5-08.8, PK 086-08.1), was discovered on 11 October 1920 by Milton Lasell Humason with spectrograms made with the 10 inch Cooke telescope on Mount Wilson Observatory. On November 9 in the same year he discovered another PN (Hu 1-1). He wrote: «Edwin Hubble observed both objects visually with the 60 inch reflector on December 9 1920. Each appeared as a small disk about 5" in diameter, the first being irregular in outline, the second nearly circular.» [504] However, there must have been a mix-up as Hu 1-1 has a round shape and Hu 1-2 is bipolar.
Physical Properties
Hu 1-2 is bipolar, hour-glass shaped nebula with fast, highly collimated outflows that have a speed of >340 km/s. This is much higher than in most PNe. Neither the morphology nor the kinematics of the central, z-shaped innermost region can be simply described as a waist or torus located between the two bipolar lobes. The knotty morphology of this region are suggestive of a ‘broken’ equatorial ring. The PN probably experienced notable violent dynamical processes during its formation. It is not clear whether the central star is a binary. The age is estimated to be less than 1100 years and the distance to 3.5 kpc. Apparent brightness: V 12.0 mag, J 11.6 mag, H 11.6 mag, K 10.9 mag. [145][505]
| Designations | PN G086.5-08.8: Hu 1-2, PK 86-08.1, Anon.21h31m, ARO 89, VV 267, VV' 553 |
| Right Ascension (J2000.0) | 21h 33m 08s |
| Declination (J2000.0) | +39° 38' 01" |
| Dimensions | 8.3" (optical), 1.7" (radio) |
| Distance | 1.6 kpc |
| Radial Velocity | -9.0 ± 8.1 km/s |
| Expansion Velocity | 29.0 (O-III) 32. (N-II) km/s |
| C-Star Designations | AG82 432 |
| C-Star Magnitude | V: 17.32 |
| Discoverer | HUMASON 1921 |
Finder Chart
The planetary nebula Hu 1-2 is located in the Milky Way of the constellation Cygnus. In the months March through December it can be seen best.
