| Emission nebula | |
|---|---|
| H II region | |
 M8, the Lagoon Nebula | |
| Observation data: J2000 epoch | |
| Right ascension | 18h 03m 37s[1] |
| Declination | −24° 23′ 12″[1] |
| Distance | 4,100[2] ly (1,250 pc) |
| Apparent magnitude (V) | 4.6[3] |
| Apparent dimensions (V) | 90 × 40 arcmins[3] |
| Constellation | Sagittarius |
| Physical characteristics | |
| Radius | 55 × 20 ly |
| Designations | Sharpless 25, RCW 146, Gum 72 M8 contains: NGC 6523, NGC 6530,[1] Hourglass nebula[4] |
The Lagoon Nebula (catalogued as Messier 8 or M8, NGC 6523, Sharpless 25, RCW 146, and Gum 72) is a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula and has an H II region.
The Lagoon Nebula was discovered by Giovanni Hodierna before 1654[5] and is one of only two star-forming nebulae faintly visible to the eye from mid-northern latitudes. Seen with binoculars, it appears as a distinct cloud-like patch with a definite core. Within the nebula is the open cluster NGC 6530.[6]
- ^ a b c "M 8". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-15.
- ^ Arias, J. I.; Barbá, R. H.; Maíz Apellániz, J.; Morrell, N. I.; Rubio, M. (2006). "The infrared Hourglass cluster in M8". Monthly Notices of the Royal Astronomical Society. 366 (3): 739–757. arXiv:astro-ph/0506552. Bibcode:2006MNRAS.366..739A. doi:10.1111/j.1365-2966.2005.09829.x. S2CID 13907667.
- ^ a b Stoyan, Ronald (2008). Atlas of the Messier Objects: Highlights of the Deep Sky. Cambridge University Press. p. 88. ISBN 978-0-521-89554-5.
- ^ "SIMBAD Astronomical Database". Results for Hourglass Nebula. Retrieved 2006-12-22.
- ^ Kronberg, Guy McArthur, Hartmut Frommert, Christine. "Messier Object 8". messier.seds.org. Retrieved 11 April 2018.
{{cite web}}: CS1 maint: multiple names: authors list (link) - ^ N. F. H. Tothill; Marc Gagné; B. Stecklum; M. A. Kenworthy (2008). "The Lagoon Nebula and its Vicinity". In Bo Reipurth (ed.). Handbook of Star-Forming Regions: Volume 2 The Southern Sky. Astronomical Society of the Pacific. p. 53. ISBN 978-1-58381-671-4.