Messier 78

Messier 78

Reflection nebula
Image of Messier 78 captured using the Wide Field Imager camera on the MPG/ESO 2.2-metre telescope at the La Silla Observatory.
Observation data: J2000.0 epoch
Right ascension	05^h 46^m 46.7^s[1]
Declination	+00° 00′ 50″[1]
Distance	1,350 ly (415 pc)[2] ly
Apparent magnitude (V)	8.3[3]
Apparent dimensions (V)	8′ × 6′[3]
Constellation	Orion
Physical characteristics
Radius	5 ly
Notable features	Part of the Orion complex
Designations	Ced 55u, DG 80, IRAS 05442-0000, [KPS2012] MWSC 0664, NGC 2068[1]
See also: Lists of nebulae

Messier 78 (also known as M78 or NGC 2068) is a reflection nebula in the constellation Orion. It is the brightest diffuse reflection nebula in a group that includes NGC 2064, NGC 2067, and NGC 2071, all part of the Orion B molecular cloud complex. Located approximately 1,350 light-years from Earth,^[2] M78 is visible in small telescopes as a hazy patch illuminated by two B-type stars, HD 38563 A and HD 38563 B, of 10th and 11th magnitude.^[4] It is a popular target for amateur astronomers, who have given it the common name Casper the Friendly Ghost Nebula.^[5]

Discovery

Discovered by Pierre Méchain in 1780, M78 was included in Charles Messier's catalog of comet-like objects that same year.^[6]

Structure and composition

The nebula's dust cloud reflects light from its two central stars, making it visible. Infrared observations reveal an embedded star cluster^[2] and a hierarchy of gas clumps with core masses ranging from 0.3 M_☉ to 5 M_☉.^[7] M78 hosts:

• 45 T Tauri stars (young stellar objects still forming).^[8]
• 17 Herbig–Haro objects (jets emitted by nascent stars).^[9]

Observations

On May 23, 2024, the European Space Agency released a high-resolution image of M78 from the Euclid mission, revealing hundreds of thousands of previously unseen objects, including substellar bodies.^[10]

Gallery

• 
  VISTA image of Messier 78.
• 
  Spitzer image of Messier 78.
• 
  Euclid image of star-forming region Messier 78
• 
  SDDS image of Messier 78.

See also

• List of Messier objects

References

1. "M 78". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 14 February 2016.
2. Walker-Smith, S. L.; Richer, J. S.; Buckle, J. V.; Smith, R. J.; Greaves, J. S.; Bonnell, I. A. (March 2013), "The structure and kinematics of dense gas in NGC 2068", Monthly Notices of the Royal Astronomical Society, 429 (4): 3252–3265, arXiv:1212.2018, Bibcode:2013MNRAS.429.3252W, doi:10.1093/mnras/sts582.
3. "Messier 78". SEDS Messier Catalog. Retrieved 30 April 2022.
4. Strom, S. E.; et al. (July 1974), "Infrared and optical observations of Herbig–Haro objects.", The Astrophysical Journal, 191: 111–142, Bibcode:1974ApJ...191..111S, doi:10.1086/152948.
5. https://www.aapod2.com/blog/messier-78-casper-the-friendly-ghost
6. Frommert, Hartmut; Kronberg, Christine (9 October 2018), "Messier 78", SEDS Messier pages, Students for the Exploration and Development of Space (SEDS), retrieved 5 December 2018.
7. Motte, F.; et al. (June 2001), "A SCUBA survey of the NGC 2068/2071 protoclusters", Astronomy and Astrophysics, 372 (3): L41–L44, arXiv:astro-ph/0105019, Bibcode:2001A&A...372L..41M, doi:10.1051/0004-6361:20010543, S2CID 7658059.
8. Herbig, G. H.; Kuhi, L. V. (February 1963), "Emission-Line Stars in the Region of NGC 2068", The Astrophysical Journal, 137: 398, Bibcode:1963ApJ...137..398H, doi:10.1086/147519.
9. Zhao, Bing; et al. (September 1999), "Newly Discovered Herbig-Haro Objects in the NGC 2068 and NGC 2071 Regions", The Astronomical Journal, 118 (3): 1347–1353, Bibcode:1999AJ....118.1347Z, doi:10.1086/301002.
10. "Euclid's new image of star-forming region Messier 78". The European Space Agency. ESA/Euclid/Euclid Consortium/NASA. 23 May 2024. Retrieved 27 May 2024.

External links

• Messier 78 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
• SEDS: Starforming Nebula M78
• NASA Astronomy Picture of the Day: M78: Stardust and Starlight (4 November 2005)
• NightSkyInfo.com – M78
• Astronomy Picture of the Day
  • M78 Wide Field 2009 November 26
  • M78 and Reflecting Dust Clouds in Orion 2010 March 2
• Haran, Brady; Haese, Paul. "M78 – Reflection Nebula". Deep Sky Videos. Nottingham Astronomy Group, University of Nottingham.