NGC 4490 | |
---|---|
![]() NGC 4490 and satellite galaxy, NGC 4485 | |
Observation data (J2000 epoch) | |
Constellation | Canes Venatici |
Right ascension | 12h 30m 36.2s [1] |
Declination | 41° 38′ 38″ [1] |
Redshift | 565 ± 3 km/s [1] |
Distance | 25.1 ± 5.0 Mly (7.7 ± 1.5 Mpc) [1] |
Apparent magnitude (V) | 9.8 |
Characteristics | |
Type | SB(s)d pec [1] |
Size | 53,000 ly |
Apparent size (V) | 6.3′ × 3.1′ [1] |
Other designations | |
Arp 269, UGC 7651, PGC 41333 [1] |
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. [2]
NGC 4490 is located 3/4° northwest of beta Canum Venaticorum and with apparent visual magnitude 9.8, can be observed with 15x100 binoculars. [3] It is a member of the Herschel 400 Catalogue. It belongs to the Canes II Group.
A stellar stream 25,000 light years long connects the two interacting galaxies. The stellar stream is made of bright knots and large gas rich pockets. Young blue hot massive stars are formed in this region. [4]
Two supernovae have been observed in NGC 4490: SN 1982F, a supernova of a unknown type and has a magnitude of16, [5] and SN 2008ax, a type II supernova with a magnitude of 13. [6] [7]
Coma Berenices is an ancient asterism in the northern sky, which has been defined as one of the 88 modern constellations. It is in the direction of the fourth galactic quadrant, between Leo and Boötes, and it is visible in both hemispheres. Its name means "Berenice's Hair" in Latin and refers to Queen Berenice II of Egypt, who sacrificed her long hair as a votive offering. It was introduced to Western astronomy during the third century BC by Conon of Samos and was further corroborated as a constellation by Gerardus Mercator and Tycho Brahe. It is the only modern constellation named for a historic person.
Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees, and also the longest at over 100 degrees. Its southern end borders Libra and Centaurus and its northern end borders Cancer. It was included among the 48 constellations listed by the 2nd century astronomer Ptolemy. Commonly represented as a water snake, it straddles the celestial equator.
The Whirlpool Galaxy, also known as Messier 51a (M51a) or NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation Canes Venatici, and was the first galaxy to be classified as a spiral galaxy. It is 7.22 megaparsecs away and 23.58 kiloparsecs (76,900 ly) in diameter.
NGC 2403 is an intermediate spiral galaxy in the constellation Camelopardalis. It is an outlying member of the M81 Group, and is approximately 8 million light-years distant. It bears a similarity to M33, being about 50,000 light years in diameter and containing numerous star-forming H II regions. The northern spiral arm connects it to the star forming region NGC 2404. NGC 2403 can be observed using 10×50 binoculars. NGC 2404 is 940 light-years in diameter, making it one of the largest known H II regions. This H II region represents striking similarity with NGC 604 in M33, both in size and location in galaxy.
Messier 108 is a barred spiral galaxy about 28 million light-years away from Earth in the northern constellation Ursa Major. It was discovered by Pierre Méchain in 1781 or 1782. From the Earth, this galaxy is seen almost edge-on.
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 4725 is an intermediate barred spiral galaxy with a prominent ring structure, located in the northern constellation of Coma Berenices near the north galactic pole. It was discovered by German-born British astronomer William Herschel on April 6, 1785. The galaxy lies at a distance of approximately 40 megalight-years from the Milky Way. NGC 4725 is the brightest member of the Coma I Group of the Coma-Sculptor Cloud, although it is relatively isolated from the other members of this group. This galaxy is strongly disturbed and is interacting with neighboring spiral galaxy NGC 4747, with its spiral arms showing indications of warping. The pair have an angular separation of 24′, which corresponds to a projected linear separation of 370 kly. A tidal plume extends from NGC 4747 toward NGC 4725.
NGC 5371 is a face-on spiral galaxy in the northern constellation Canes Venatici. It was discovered on January 14, 1788 by German-British astronomer William Herschel. The nearby NGC 5390 appears to be a duplicate entry for NGC 5371, since there is nothing at the former's position. NGC 5371 has an apparent magnitude of 11.3 and an angular size of 4.4′ × 3.5′. It is located at a distance of 129.5 ± 32.4 million light-years (39.70 ± 9.92 Mpc) from the Milky Way, and is receding with a heliocentric radial velocity of 2,552 km/s. The galaxy appears to be weakly interacting with the nearby, equidistant Hickson 68 group of galaxies, and thus may be a member. Collectively, they are sometimes dubbed the Big Lick galaxy group, after the city of Roanoke, Virginia.
NGC 3432 is an edge-on spiral galaxy that can be found in the northern constellation of Leo Minor. It was discovered by German-British astronomer William Herschel on March 19, 1787. This galaxy is located at a distance of 40 million light-years (12.3 Mpc) from the Milky Way. It is interacting with UGC 5983, a nearby dwarf galaxy, and features tidal filaments and intense star formation. Because of these features, it was listed in Halton Arp's Atlas of Peculiar Galaxies.
NGC 23 is a spiral galaxy located in the northern constellation of Pegasus, around 173.5 megalight-years distant from the Milky Way. It was discovered by William Herschel on 10 September 1784. In the Webb Society Deep-Sky Observer's Handbook, the visual appearance of NGC 23 is described as follows:
Bright, extended ellipse; a bright nuclear structure is noticeably elongated; two weak spiral enhancements emerge from opposite sides of the nucleus, one curving towards a bright star attached on the south end. The galaxy is likely interacting with NGC 9.
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 4485 is an irregular galaxy located in the northern constellation of Canes Venatici. It was discovered January 14, 1788 by William Herschel. This galaxy is located at a distance of 29 million light years and is receding with a heliocentric radial velocity of 483 km/s.
NGC 3021 is a spiral galaxy in the northern constellation of Leo Minor. It is about 93 million light-years away from Earth, and is receding with a heliocentric radial velocity of 1,537±4 km/s. This galaxy was discovered December 7, 1785 by Anglo-German astronomer William Herschel. The morphological classification of NGC 3021 is SA(rs)bc, which indicates a spiral galaxy with no central bar (SA), an incomplete inner ring structure (rs), and moderate to loosely wound spiral arms (bc).
NGC 3191 is a barred spiral galaxy in the constellation Ursa Major. It is located at a distance of about 400 million light years from Earth, which, given its apparent dimensions, means that NGC 3191 is about 115,000 light years across. The galaxy has been distorted and interacts with a companion 1.3 arcminutes to the west. An extremely blue tidal bridge lies between them. It was discovered by Gaia on 23 May 2017.
NGC 6753 is a massive unbarred spiral galaxy, seen almost exactly face-on, in the southern constellation of Pavo. It was discovered by the English astronomer John Herschel on July 5, 1836. The galaxy is located at a distance of 142 million light years from the Milky Way, and is receding with a heliocentric radial velocity of 3,140 km/s. It does not display any indications of a recent interaction with another galaxy or cluster.
NGC 5395 is an interacting spiral galaxy located at a distance of 160 million light years, but receding away from the Earth at 3511 kilometers per second, in the constellation Canes Venatici. It was discovered by William Herschel on May 16, 1787. NGC 5395 and NGC 5394 are included in the Atlas of Peculiar Galaxies as Arp 84 in the category "Spiral galaxies with large high surface brightness companions".
NGC 5728 is an active barred spiral galaxy located 146 million light years away in the southern constellation of Libra. It was discovered on May 7, 1787 by William Herschel. The designation comes from the New General Catalogue of J. L. E. Dreyer, published in 1888. It has an apparent visual magnitude of 13.40 and spans an angle of 3.4 arcminutes. The galaxy shows a red shift of 0.00935 and has a heliocentric radial velocity of 2,803 km/s. It has an estimated mass of 72 billion times the mass of the Sun and stretches around 30 kpc across.
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.
NGC 7222 is a large barred spiral galaxy with a ring structure, located in the constellation Aquarius. It is located 570 million light-years away from the Solar System and was discovered by German astronomer, Albert Marth on August 11, 1864.
NGC 4332 is a barred spiral galaxy and a starburst galaxy located 128 million light-years away in the constellation Draco. The galaxy was discovered by astronomer William Herschel on March 20, 1790. NGC 4332 is host to a supermassive black hole with an estimated mass of 9.5×107 solar masses.