Planetary Nebula NGC 2022

NGC 2022
NGC 2022: Planetary nebula NGC 2022; 500/2500mm Newton + SBIG ST-6; Observatory Bülach; © 1996 Stefan Meister

History

NGC 2022 was discovered on December 28, 1785 by Wilhelm Herschel with his 18.7 inch reflecting telescope and cataloged as IV 34. He wrote about it: «Considerably bright, small, nearly round, like a star with large diameter, with 240x like an ill defined planetary nebula.» [464]

Physical Properties

NGC 2022 is a young planetary nebula with two visible shells. According to the Vorontsov-Velyaminov classification, it is described as a regular disk with a ring structure (IV, II).

Sabbadin et al. (Astron. Astrophys., 136, 193, 1984) have derived the following model for NGC 2022: The main part of the nebula is an oblate spheroid with moderate eccentricity. The axis ratio of length to width is 1.2. The whole complex is surrounded by a fainter, nearly spherical region that is expanding less rapidly than the central region. Assuming a distance of 2100 pc for the planetary nebula, this results in a diameter of 0.65 light years.

— 1996, Philipp Reza Heck

NGC 2022
NGC 2022: Planetary nebula in Orion; 500 mm Cassegrain 5800 mm f/11.4; SBIG STL11K; 28+10+10+10 min LRGB; Bernese Highlands; © 2005 Radek Chromik
NGC 2022
NGC 2022: Planetary nebula in Orion; Takahashi Mewlon 250 CR, Reducer CR 0.73 (f=1800mm / f7.25), SBIG ST-8300; 9L x 300 sec 1×1, 5R, 5G, 5B 2×2 x 300 sec; Bernese Highlands; © 2017 Bernhard Blank, Dragan Mihajlovic
«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
DesignationsPN G196.6-10.9: NGC 2022, PK 196-10.1, ARO 61, VV 23, VV' 34
Right Ascension (J2000.0)5h 42m 07s
Declination (J2000.0)9° 05' 19"
Dimensions 19." (optical)
Distance 1.8 kpc
Radial Velocity+14.0 km/s ± 2.0 km/s
Expansion Velocity 26. km/s (O-III)
C-Star DesignationsAG82 49, HD 37882, PLX 1306
C-Star Magnitude15.89 mag (B filter)
DiscovererHERSCHEL 1785

Finder Chart

The planetary nebula NGC 2022 lies in the constellation of Orion between Betelgeuse (α Orionis) and Meisse (λ Orionis). (one third of the way from λ Orionis to Betelgeuse, just under 2 degrees). Surrounding mag 3.4 Meissa are numerous stars arranged in a conspicuous pattern that appears to the unaided eye like a loose, open star cluster. From there you come across the small nebula after almost 2 degrees or about a third of the distance between Meissa and Betelgeuse. The best observation time is October to February.

Chart NGC 2022
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

Visual Observation

NGC 2022
NGC 2022: Zeichnung; 200mm SCT, 226x; © 1996 Philipp Reza Heck

200 mm aperture: The PN appears as an almost circular object. At 80 km/h Mistral neither the ring nor the central star could be seen. The very small extent of NGC 2022 requires high magnifications and therefore reasonably good seeing.

250 mm aperture: Although only just visible at 50x, at high magnification the nebula reveals a ring-shaped disk about 25 arc seconds in diameter which appears completely black on the inside.

300 mm aperture: Here the nebula already looks less even. A slight elongation is visible at position angle 15 degrees, the extent of the structure is 25" x 20". There are bright points at the two outer ends of the ring, with the southern one appearing more conspicuous. At 450x magnification, the nebula is clearly ring-shaped but still lacks a central star.

— 1996, Philipp Reza Heck

References

141Strasbourg-ESO Catalogue of Galactic Planetary Nebulae; A. Acker, F. Ochsenbein, B. Stenholm, R. Tylenda, J. Marcout, C. Schohn; European Southern Observatory; ISBN 3-923524-41-2 (1992); cdsarc.unistra.fr/viz-bin/cat/V/84 (2021-02-18)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
464«Catalogue of a second thousand of new nebulae and clusters of stars; with a few introductory remarks on the construction of the heavens» William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1789; DOI:10.1098/rstl.1789.0021