NGC 2442 / 2443 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Volans |
Right ascension | 07h 36m 23.8s [2] |
Declination | −69° 31′ 51″ [2] |
Redshift | 1466 ± 5 km/s [2] |
Apparent magnitude (V) | 11.2 [2] |
Characteristics | |
Type | SAB(s)bc pec [2] |
Apparent size (V) | 5′.5 × 4′.9 [2] |
Notable features | SW part is NGC 2442 while NE part is NGC 2443 |
Other designations | |
PGC 21373 [2] |
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. [3] 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 (his "20-foot telescope") from an observatory he set up in Cape Town, South Africa. [4] Associated with this galaxy is HIPASS J0731-69, a cloud of gas devoid of any stars. [5] It is likely that the cloud was torn loose from NGC 2442 by a companion. [5]
When John Louis Emil Dreyer compiled the New General Catalogue of Nebulae and Clusters of Stars he used William Herschel's earlier observations that described two objects in a "double nebula", giving the northern most the designation NGC 2443 and the southernmost most the designation NGC 2442. Herschel's later observations noted that the two objects were actually a single large nebula. [4] [6]
Two, or perhaps three, supernovae have been observed in NGC 2442:
Messier 66 or M66, also known as NGC 3627, is an intermediate spiral galaxy in the southern, equatorial half of Leo. It was discovered by French astronomer Charles Messier on 1 March 1780, who described it as "very long and very faint". This galaxy is a member of a small group of galaxies that includes M65 and NGC 3628, known as the Leo Triplet or the M66 Group. M65 and M66 are a common object for amateur astronomic observation, being separated by only 20′.
NGC 3184, the Little Pinwheel Galaxy, is a spiral galaxy approximately 40 million light-years away in the constellation Ursa Major. Its name comes from its resemblance to the Pinwheel Galaxy. It was discovered on 18 March 1787 by German-British astronomer William Herschel. It has two HII regions named NGC 3180 and NGC 3181.
NGC 6946, sometimes referred to as the Fireworks Galaxy, is a face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs, similar to the distance of M101 in the constellation Ursa Major. Both were once considered to be part of the Local Group, but are now known to be among the dozen bright spiral galaxies near the Milky Way but beyond the confines of the Local Group. NGC 6946 lies within the Virgo Supercluster.
NGC 4414, also known as the Dusty Spiral Galaxy, is an unbarred spiral galaxy about 62 million light-years away in the constellation Coma Berenices. It was discovered by German-British astronomer William Herschel on 13 March 1785.
NGC 1316 is a lenticular galaxy about 60 million light-years away in the constellation Fornax. It is a radio galaxy and at 1400 MHz is the fourth-brightest radio source in the sky.
NGC 5253 is an irregular galaxy in the constellation Centaurus. It was discovered by William Herschel on 15 March 1787.
NGC 1566, sometimes known as the Spanish Dancer, is an intermediate spiral galaxy in the constellation Dorado, positioned about 3.5° to the south of the star Gamma Doradus. It was discovered on May 28, 1826 by Scottish astronomer James Dunlop. At 10th magnitude, it requires a telescope to view. The distance to this galaxy remains elusive, with measurements ranging from 6 Mpc up to 21 Mpc.
NGC 2770 is a spiral galaxy in the northern constellation of Lynx, near the northern constellation border with Cancer. It was discovered by German-born astronomer William Herschel on December 7, 1785. J. L. E. Dreyer described it as, "faint, large, much extended 150°, mottled but not resolved, 2 stars to north". NGC 2770 was the target for the first binocular image produced by the Large Binocular Telescope.
Arp 271 is a pair of similarly sized interacting spiral galaxies, NGC 5426 and NGC 5427, in the constellation of Virgo. It is not certain whether the galaxies are going to eventually collide or not. They will continue interacting for tens of millions of years, creating new stars as a result of the mutual gravitational attraction between the galaxies, a pull seen in the bridge of stars already connecting the two. Located about 130 million light-years away, the Arp 271 pair is about 130,000 light-years across. It was originally discovered in 1785 by William Herschel. It is speculated, that the Milky Way will undergo a similar collision in about five billion years with the neighbouring Andromeda Galaxy, which is currently located about 2.6 million light-years away.
NGC 3938 is an unbarred spiral galaxy in the Ursa Major constellation. It was discovered on 6 February 1788 by William Herschel. It is one of the brightest spiral galaxies in the Ursa Major South galaxy group and is roughly 67,000 light years in diameter. It is approximately 43 million light years away from Earth. NGC 3938 is classified as type Sc under the Hubble sequence, a loosely wound spiral galaxy with a smaller and dimmer bulge. The spiral arms of the galaxy contain many areas of ionized atomic hydrogen gas, more so towards the center.
NGC 3198, also known as Herschel 146 is a barred spiral galaxy in the constellation Ursa Major. It was discovered by William Herschel on 15 January 1788. NGC 3198 is located in the Leo Spur, which is part of the Virgo Supercluster, and is approximately 47 million light years away.
NGC 488 is a face-on spiral galaxy in the constellation Pisces. It was discovered by German-British astronomer William Herschel on 13 December 1784. It is at a distance of about 90 million light-years away from Earth. Its diameter is estimated to be 52,6 Kpc. The galaxy has a large central bulge, and is considered a prototype galaxy with multiple spiral arms. Its arms are tightly wound. Star forming activity has been traced within the arms. The nucleus of NGC 488 has been found to be chemically decoupled, being twice as metal rich as the central bulge of the galaxy. NGC 488, with the exception of its smaller companions, that form NGC 488 group, is an isolated galaxy.
NGC 524 is a lenticular galaxy in the constellation Pisces. It is at a distance of about 90 million light-years away from Earth. In the central bulge of the galaxy is visible gas forming a spiral structure. It is the largest galaxy in the small NGC 524 group of galaxies, which is associated with NGC 488 and its group. It was discovered by William Herschel on 4 September 1786.
NGC 1084 is an unbarred spiral galaxy in the constellation Eridanus. It is located at a distance of about 63 million light-years away from the Milky Way. The galaxy was discovered by William Herschel on 10 January 1785. It has multiple spiral arms, which are not well defined. It belongs in the same galaxy group with NGC 988, NGC 991, NGC 1022, NGC 1035, NGC 1042, NGC 1047, NGC 1052 and NGC 1110. This group is in turn associated with the Messier 77 group.
NGC 908 is an unbarred spiral galaxy in the constellation Cetus. It was discovered on 20 September 1786 by William Herschel. This galaxy is 56 million light years away from Earth. It is the main galaxy in the NGC 908 group, which also includes NGC 899, NGC 907, and IC 223.
NGC 4490, also known as the Cocoon Galaxy, is a barred spiral galaxy in the constellation Canes Venatici. William Herschel discovered it in 1788. It is known to be of the closest interacting/merging galactic system. The galaxy lies at a distance of 25 million light years from Earth making it located in the local universe. It interacts with its smaller companion NGC 4485 and as a result is a starburst galaxy. NGC 4490 and NGC 4485 are collectively known in the Atlas of Peculiar Galaxies as Arp 269. The two galaxies has already made their closest approach and are rushing away from each other. It's been discovered that NGC 4490 has a double nucleus.
NGC 4699 is an intermediate spiral galaxy located in the constellation Virgo. It is located at a distance of about 65 million light years from Earth, which, given its apparent dimensions, means that NGC 4699 is about 85,000 light years across. It was discovered by William Herschel in 1786. It is a member of the NGC 4699 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.
NGC 521, also occasionally referred to as PGC 5190 or UGC 962, is a barred spiral galaxy located approximately 224 million light-years from the Solar System in the constellation Cetus. It was discovered on 8 October 1785 by astronomer William Herschel.
NGC 7606 is a spiral galaxy located in the constellation Aquarius. It is located at a distance of circa 100 million light years from Earth, which, given its apparent dimensions, means that NGC 7606 is about 165,000 light years across. It was discovered by William Herschel on September 28, 1785. The galaxy is included in the Herschel 400 Catalogue. It lies 45 arcminutes northeast from psi2 Aquarii. It can be seen with a 4 inch telescope but its visibility is greatly affected by light pollution.
NGC 1325 is a flocculent spiral galaxy situated in the constellation of Eridanus. Located about 75 million light years away, it is a member of the Eridanus cluster of galaxies, a cluster of about 200 galaxies. It was discovered by William Herschel on 19 December 1799.