NGC 6891

NGC 6891
Nebula
Planetary nebula
Hubble Space Telescope image of NGC 6891
Observation data: J2000.0 epoch
Right ascension20h 15m 08.84s
Declination+12° 42′ 15.6″
Distance12,400 ly
Apparent magnitude (V)12.51±0.23
ConstellationDelphinus
DesignationsPN G054.1-12.1, PK 54-12.1, IRAS 20127+1233
See also: Lists of nebulae

NGC 6891 is a bright, asymmetrical planetary nebula located in the northern constellation of Delphinus. It was discovered on 22 September 1884, by Scottish astronomer Ralph Copeland, who observed it using visual spectroscopy with a 6.1-inch refractor at the Dun Echt Observatory in Aberdeen, Scotland.

Characteristics

NGC 6891 displays a triple-shell structure, consisting of a bright inner nebula, an attached intermediate shell, and a detached outer halo. High-resolution imaging reveals filaments, knots, and intricate details in the interior surrounding the central white dwarf star named HD 192563, along with at least two ellipsoidal shells oriented differently and a spherical outer halo expanding faster than the inner regions. The bright optical regions have an apparent diameter of approximately 15 arcseconds. The nebula shows evidence of multiple mass ejection episodes from its progenitor star.

Observation

NGC 6891 has an apparent visual magnitude of around 10.5 to 12 and appears as a small, bluish disc in amateur telescopes of 6 inches (150 mm) aperture or larger, with the central star faintly visible under good conditions. It lies near the celestial equator in Delphinus and is observable from both hemispheres. The nebula has been imaged in detail by the Hubble Space Telescope, contributing to studies of planetary nebula structure, formation, evolution, and distance determination.

References

  1. 1 2 3 4 "Simbad - Object view". simbad.cds.unistra.fr. Retrieved 2026-03-06.
  2. ↑ Stanghellini, Letizia; Shaw, Richard A.; Villaver, Eva (2008). "The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale". The Astrophysical Journal. 689 (1): 194–202. arXiv:0807.1129. doi:10.1086/592395. ISSN 0004-637X.
  3. 1 2 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. ISSN 0004-6361.
  4. 1 2 3 "Hubble's View of Planetary Nebula Reveals Complex Structure - NASA Science". 2021-11-29. Retrieved 2026-03-06.
  5. ↑ Lazaro, Enrico de (2021-11-30). "Hubble Spots Beautiful Planetary Nebula: NGC 6891 | Sci.News". Sci.News: Breaking Science News. Retrieved 2026-03-06.
  6. 1 2 "NGC 6891 - Planetary Nebula in Delphinus | TheSkyLive". theskylive.com. Retrieved 2026-03-06.
  7. 1 2 "Planetary Nebula NGC 6891 | Deep⋆Sky Corner". www.deepskycorner.ch. Retrieved 2026-03-06.
  8. 1 2 Guerrero, Martín A.; Miranda, Luis F.; Manchado, Arturo; Vázquez, Roberto (2000). "The triple-shell structure and collimated outflows of the planetary nebula NGC 6891". Monthly Notices of the Royal Astronomical Society. 313 (1): 1–7. arXiv:astro-ph/9910378. doi:10.1046/j.1365-8711.2000.03159.x. ISSN 0035-8711.
  9. ↑ Palen, Stacy; Balick, Bruce; Hajian, Arsen R.; Terzian, Yervant; Bond, Howard E.; Panagia, Nino (2002). "Hubble Space Telescope Expansion Parallaxes of the Planetary Nebulae NGC 6578, NGC 6884, NGC 6891, and IC 2448". The Astronomical Journal. 123 (5): 2666–2675. arXiv:astro-ph/0202003. doi:10.1086/339838. ISSN 0004-6256.