Planetary Nebula Humason 1-2

Humason 1-2
Humason 1-2: Planetary Nebula in Cygnus; 500 mm Cassegrain f=3625 mm f/7.2; SBIG STL11K; 6-3-3-3 min LRGB; Bernese Highlands; © 2011 Radek Chromik [32]


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.

Humason 1-2
Humason 1-2: Colour-composite picture of Hu 1-2 in the [N II] (red), Hα (green), and [O III] (blue) emission lines. Image taken with the 2.5 m Nordic Optical Telescope (NOT) on La Palma, Spain [505]

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]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
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 to December it can be seen best.

Finder Chart Planetary Nebula Humason 1-2
Planetary Nebula Humason 1-2 in constellation Cygnus. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Objects Within a Radius of 15°