Emission nebula | |
---|---|
Observation data: J2000 epoch | |
Right ascension | 05h 39m 03.0s [3] |
Declination | −69° 29′ 54″ [3] |
Distance | 170,000 ly (52,000 pc) |
Constellation | Dorado [1] |
Designations | GC 1272, JH 2942 |
NGC 2074 is a magnitude ~8 emission nebula in the Tarantula Nebula located in the constellation Dorado. It was discovered on 3 August 1826 by James Dunlop and around 1835 by John Herschel. It is described as being "pretty bright, pretty large, much extended, [and having] 5 stars involved". [3]
Some of the objects catalogued by Herschel before 1847 do not have a discovery date listed, and NGC 2074 is one of them. Though its inclusion in the catalog of objects observed in the Large Magellanic Cloud which involves observations carried out between 2 November 1836 and 26 March 1837 shows it must not have been discovered later than that. [3]
The observation of NGC 2074 by Dunlop was not identified as this object until recently. [3]
NGC 2074 is located around 170,000 light-years (1.1×1010 AU) away. The area has a lot of raw stellar creation, possibly triggered by a nearby supernova explosion and is on the edge of a dark molecular cloud which is an incubator for the birth of new stars. [2]
An emission nebula is a nebula formed of ionized gases that emit light of various wavelengths. The most common source of ionization is high-energy ultraviolet photons emitted from a nearby hot star. Among the several different types of emission nebulae are H II regions, in which star formation is taking place and young, massive stars are the source of the ionizing photons; and planetary nebulae, in which a dying star has thrown off its outer layers, with the exposed hot core then ionizing them.
The Carina Nebula or Eta Carinae Nebula is a large, complex area of bright and dark nebulosity in the constellation Carina, located in the Carina–Sagittarius Arm of the Milky Way galaxy. The nebula is approximately 8,500 light-years (2,600 pc) from Earth.
The Orion molecular cloud complex is a star-forming region with stellar ages ranging up to 12 Myr. Two giant molecular clouds are a part of it, Orion A and Orion B. The stars currently forming within the complex are located within these clouds. A number of other somewhat older stars no longer associated with the molecular gas are also part of the complex, most notably the Orion's Belt, as well as the dispersed population north of it. Near the head of Orion there is also a population of young stars that is centered on Meissa. The complex is between 1 000 and 1 400 light-years away, and hundreds of light-years across.
Sh2-279 is an HII region and bright nebulae that includes a reflection nebula located in the constellation Orion. It is the northernmost part of the asterism known as Orion's Sword, lying 0.6° north of the Orion Nebula. The reflection nebula embedded in Sh2-279 is popularly known as the Running Man Nebula.
NGC 2442 and NGC 2443 are two parts of a single intermediate spiral galaxy, commonly known as the Meathook Galaxy or the Cobra and Mouse. It is about 50 million light-years away in the constellation Volans. It was discovered by Sir John Herschel on December 23, 1834 during his survey of southern skies with a 18.25 inch diameter reflecting telescope from an observatory he set up in Cape Town, South Africa. Associated with this galaxy is HIPASS J0731-69, a cloud of gas devoid of any stars. It is likely that the cloud was torn loose from NGC 2442 by a companion.
NGC 2080, also known as the Ghost Head Nebula, is a star-forming region and emission nebula to the south of the 30 Doradus (Tarantula) nebula, in the southern constellation Dorado. It belongs to the Large Magellanic Cloud, a satellite galaxy to the Milky Way, which is at a distance of 168,000 light years. NGC 2080 was discovered by John Frederick William Herschel in 1834. The Ghost Head Nebula has a diameter of 50 light-years and is named for the two distinct white patches it possesses, called the "eyes of the ghost". The western patch, called A1, has a bubble in the center which was created by the young, massive star it contains. The eastern patch, called A2, has several young stars in a newly formed cluster, but they are still obscured by their originating dust cloud. Because neither dust cloud has dissipated due to the stellar radiation, astronomers have deduced that both sets of stars formed within the past 10,000 years. These stars together have begun to create a bubble in the nebula with their outpourings of material, called stellar wind.
NGC 2023 is an emission and reflection nebula in the equatorial constellation of Orion. It was discovered by the German-born astronomer William Herschel on 6 January 1785. This reflection nebula is one of the largest in the sky, with a size of 10 × 10 arcminutes. It is located at a distance of 1,300 ly (400 pc) from the Sun, and is positioned ~15′ to the northeast of the Horsehead Nebula.
NGC 346 is a young open cluster of stars with associated nebula located in the Small Magellanic Cloud (SMC) that appears in the southern constellation of Tucana. It was discovered August 1, 1826 by Scottish astronomer James Dunlop. J. L. E. Dreyer described it as, "bright, large, very irregular figure, much brighter middle similar to double star, mottled but not resolved". On the outskirts of the cluster is the multiple star system HD 5980, one of the brightest stars in the SMC.
NGC 5307 is a planetary nebula in the southern constellation of Centaurus, positioned less than 3° to the northeast of the star Epsilon Centauri. It was discovered by English astronomer John Herschel on April 15, 1836. The nebula is located at a distance of approximately 10.6 kilolight-years from the Sun. The central star, designated PNG 312.3+10.5, is a weak emission-line star, superficially similar to the WC subtype of Wolf–Rayet stars. It has a spectral class of O(H)3.5 V.
NGC 2261 is a variable nebula located in the constellation Monoceros. The nebula is illuminated by the star R Monocerotis, which is not directly visible itself.
NGC 3195 is a planetary nebula located in the southern constellation of Chamaeleon. Discovered by Sir John Herschel in 1835, this 11.6 apparent magnitude planetary nebula is slightly oval in shape, with dimensions of 40×35 arc seconds, and can be seen visually in telescopic apertures of 10.5 centimetres (4.1 in) at low magnifications.
NGC 3242 is a planetary nebula located in the constellation Hydra.
The Little Gem Nebula or NGC 6818 is a planetary nebula located in the constellation of Sagittarius. It has magnitude 10 and oval diameter of 15 to 22 arcseconds with a 15th magnitude central star.
The Heart Nebula is an emission nebula, 7500 light years away from Earth and located in the Perseus Arm of the Galaxy in the constellation Cassiopeia. It was discovered by William Herschel on 3 November 1787. It displays glowing ionized hydrogen gas and darker dust lanes.
NGC 460 is an open cluster with nebula located in the constellation Tucana. It was possibly observed on August 1, 1826, by James Dunlop, although it was officially discovered on April 11, 1834, by John Herschel. It was described by Dreyer as "very faint .", with Nubecular Minor being the Small Magellanic Cloud. It was also described by DeLisle Stewart as "faint, pretty large, irregularly round, gradually brighter middle, mottled but not resolved, 2nd of several."
NGC 1858 is a bright, large, irregular open cluster and emission nebula. It is found in the Dorado constellation. It is located in the Large Magellanic Cloud. It was first discovered by James Dunlop on August 3, 1826, and was first recorded as Dunlop 120. John Herschel recorded it on November 2, 1834. However, at the time, he did not associate it with Dunlop 120. Astronomers have now realised that Dunlop 120 and NGC 1858 are the same object.
NGC 1936 is an emission nebula which is part of the larger LMC-N44 nebula located in the Dorado constellation in the Large Magellanic Cloud. It was discovered by John Herschel in 1834 and added to the Catalogue of Nebulae and Clusters of Stars as NGC 1936. It was later observed by John Dunlop on September 27, 1936, and Williamina Fleming in 1901 and added to the Index Catalogue as IC 2127. Its apparent magnitude is 11.60.
NGC 1974 is an open cluster associated with an emission nebula which is located in the Dorado constellation which is part of the Large Magellanic Cloud. It was discovered by James Dunlop on November 6, 1826, and later observed by John Herschel on January 2, 1837, subsequently cataloged as NGC 1991. Its apparent magnitude is 9.0 and its size is 1.7 arc minutes.
NGC 1712, also known as GC 942, JH 2685, and Dunlop 112 is an open cluster in the constellation of Dorado. It is relatively small, and is located inside the Large Magellanic Cloud. NGC 1712 was originally discovered in 1826 by James Dunlop, although Herschel rediscovered it in 1834. Nine variable stars have been discovered in it so far, with three suspected to be binary systems.