NGC 2022
Emission nebula
Planetary nebula
NGC 2022 taken by HST.[1]
Observation data: J2000 epoch
Right ascension05h 42m 06.19056s[2]
Declination+09° 05′ 10.5843″[2]
Distance8.21 kly (2.518 kpc)[3] ly
Apparent magnitude (V)11.6[4]
Apparent dimensions (V)28″[4]
ConstellationOrion
Physical characteristics
Radius0.326 ± 0.039 ly[5] ly
Notable featuresDouble-shell
DesignationsPK 196-10 1, IRAS 05393+0903[6]

NGC 2022 is a planetary nebula in the equatorial constellation of Orion, located at a distance of 8.21 kilolight-years from the Sun.[3] It was first observed by William Herschel on December 28, 1785, who described it as: considerably bright, nearly round, like a star with a large diameter, like an ill-defined planetary nebula.[7] In medium-sized amateur telescopes it looks like a small grayish patch of light. It is not very bright but it is still easy to spot it in the eyepiece. Even in a telescope as small as 80mm it can just be seen using a narrowband filter such as an OIII filter as a 'fuzzy' star. The object has the shape of a prolate spheroid with a major to minor axis ratio of 1.2,[4] an apparent size of 28″, and a halo extending out to 40″, which is about the angular diameter of Jupiter as seen from Earth.[8]

This is a double-shell planetary nebula with a wind-compressed inner shell and a more nebulous second shell.[9] The linear radius of the inner shell is estimated at 0.326 ± 0.039 ly. It is expanding with a velocity of 28±2 km/s. The second shell is nearly circular and is expanding more slowly than the inner.[5] The mass of the ionized elements in the planetary nebula is 0.19 M☉, or 19% of the Sun's mass.[5] A faint outer halo consists of the remains of material ejected during the central star's asymptotic giant branch stage.[10]

NGC 2022 lies 11° away from the Galactic Plane, which position suggests it was formed from a low-mass star. The elemental abundances are similar to those in the Sun, although carbon is about 50% higher and sulfur is a factor of two lower.[8] The central star of this nebula has a visual magnitude of 15.92, a temperature of 122,000 K, and is radiating 852 times the luminosity of the Sun from a photosphere that has only 6.55% of the Sun's radius.[8]

References

  1. ↑ "The Inky Abyss". www.spacetelescope.org. Retrieved 12 August 2019.
  2. 1 2 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  3. 1 2 Stanghellini, Letizia; et al. (2008), "The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale", The Astrophysical Journal, 689 (1): 194–202, arXiv:0807.1129, Bibcode:2008ApJ...689..194S, doi:10.1086/592395, S2CID 119257242.
  4. 1 2 3 Finlay, Warren H. (2014), Concise Catalog of Deep-sky Objects, The Patrick Moore Practical Astronomy Series (2nd ed.), Springer Science & Business Media, p. 188, ISBN 978-3-319-03169-9.
  5. 1 2 3 Sabbadin, F.; et al. (July 1984), "The planetary nebulae NGC 1535 and NGC 2022.", Astronomy and Astrophysics, 136: 193–199, Bibcode:1984A&A...136..193S.
  6. ↑ "NGC 2022". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-04-11.
  7. ↑ O'Meara, Stephen James (2011), Deep-Sky Companions: The Secret Deep, vol. 4, Cambridge University Press, p. 111, ISBN 9781139500074.
  8. 1 2 3 Pottasch, S. R.; et al. (June 2005), "Abundances of planetary nebulae NGC 2022, NGC 6818 and IC 4191", Astronomy and Astrophysics, 436 (3): 953–965, Bibcode:2005A&A...436..953P, doi:10.1051/0004-6361:20042627.
  9. ↑ Kaler, James B., "NGC 2022 in Orion", STARS, retrieved 2020-04-12.
  10. ↑ Corradi, R. L. M.; et al. (April 2003), "Ionized haloes in planetary nebulae: new discoveries, literature compilation and basic statistical properties", Monthly Notices of the Royal Astronomical Society, 340 (2): 417–446, Bibcode:2003MNRAS.340..417C, doi:10.1046/j.1365-8711.2003.06294.x.
  • Media related to NGC 2022 at Wikimedia Commons
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.