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


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]

DesignationsPN 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 km/s ± 8.1 km/s
Expansion Velocity 29.0 km/s (O-III), 32. km/s (N-II)
C-Star DesignationsAG82 432
C-Star Magnitude17.32 mag (V filter)
DiscovererHUMASON 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.

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]

Visual Observation

Pending ...

More Objects Nearby (±15°)


145SIMBAD astronomical database;
149SkySafari 6 Pro, Simulation Curriculum;
160The STScI Digitized Sky Survey;
504«Two New Planetary Nebulae» M. L. Humason; Publications of the Astronomical Society of the Pacific, Volume 33, Number 193, 1921; DOI:10.1086/123071
505«Hu 1-2: a metal-poor bipolar planetary nebula with fast collimated outflows» X. Fang, M. A. Guerrero, L. F. Miranda, A. Riera, P. F. Velázquez, A. C. Raga; Monthly Notices of the Royal Astronomical Society, Volume 452, Issue 3, 21 September 2015, Pages 2445–2462; DOI:10.1093/mnras/stv1477