barred spiral galaxy
A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies in the local universe, and generally affect both the motions of stars and interstellar gas ...
in the constellation
Canes Venatici
Canes Venatici ( ) is one of the 88 constellations designated by the International Astronomical Union (IAU). It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for 'hunting dogs', and ...
. It was discovered by German-British astronomer
William Herschel
Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...
on 14 January 1788. It is known to be of the closest interacting/merging galactic system. The galaxy lies at a distance of 25 million
light years
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astro ...
from Earth making it located in the local
universe
The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...
. It interacts with its smaller companion NGC 4485 and as a result is a
starburst galaxy
A starburst galaxy is one undergoing an exceptionally high rate of star formation, as compared to the long-term average rate of star formation in the galaxy, or the star formation rate observed in most other galaxies.
For example, the star format ...
. NGC 4490 and NGC 4485 are collectively known in the
Atlas of Peculiar Galaxies
The ''Atlas of Peculiar Galaxies'' is a Astronomical catalog, catalog of peculiar galaxies produced by Halton Arp in 1966. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institut ...
as Arp 269. The two galaxies have already made their closest approach and are rushing away from each other. It has been discovered that NGC 4490 has a double nucleus.
NGC 4490 is located 3/4° northwest of
beta Canum Venaticorum
Beta Canum Venaticorum (β Canum Venaticorum, abbreviated Beta CVn, β CVn), also named Chara , is the second-brightest star in the northern constellation of Canes Venatici. It is a nearby solar-type star, about distant based on its stell ...
and with apparent visual magnitude 9.8, can be observed with 15x100
binoculars
Binoculars or field glasses are two refracting telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most binoculars are sized to be held ...
. It is a member of the
Herschel 400 Catalogue
The Herschel 400 catalogue is a subset of William Herschel, William Herschel's original ''Catalogue of Nebulae and Clusters of Stars'', selected by Brenda F. Guzman (Branchett), Lydel Guzman, Paul Jones, James Morris, Peggy Taylor and Sara Saey of ...
. It belongs to the Canes II Group. NGC 4490 has a system of
satellite galaxies
A satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and Luminosity, luminous host galaxy (also known as the primary galaxy). Satellite galaxies and their constituents ...
oriented roughly in a plane.
Stellar stream
A
stellar stream
In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space.
Stellar kinematics encompasses the measurement of stellar velocities in the Milky Way and its satellites as well as ...
25,000 light years long connects the two
interacting galaxies
Interacting galaxies (''colliding galaxies'') are galaxies whose gravitational fields result in a disturbance of one another. Major mergers occur between galaxies with similar amounts of mass, whereas minor mergers involve galaxies with masses ...
. The stellar stream is made of bright knots and large
gas
Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as ...
rich pockets. Young blue hot massive
stars
A star is a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixed points of ...
are formed in this region.
Supernovae and Luminous Red Nova
Two
supernova
A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...
e and one
luminous red nova
A luminous red nova (abbr. ''LRN'', pl. ''luminous red novae'', pl.abbr. ''LRNe'') is a stellar explosion thought to be caused by the merging of two stars. They are characterised by a distinct red colour, and a light curve that fades slowly with ...
(LRN) have been observed in NGC 4490:
* SN 1982F (type unknown, mag. 16) was discovered by Paul Wild on 15 April 1982.
* AT 2011kp (type LRN, mag. 16.7) was discovered by Giancarlo Cortini and Stefano Antonellini on 16 August 2011.
* SN 2008ax ( type II, mag. 13) was discovered by the
Lick Observatory
The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton (California), Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The ...
Supernova Search (LOSS) on 3 March 2008 and by
Kōichi Itagaki
is an amateur astronomer based in Yamagata, the capital city of Yamagata Prefecture in the Tōhoku region of northern Honshu island, Japan. He is responsible for discovering many comets, and over 170 supernovae.
Gallery
Result of a galactic crash.jpg, Extreme tidal forces have carved out the shapes and properties of NGC 4490.
See also
*
Barred spiral galaxy
A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies in the local universe, and generally affect both the motions of stars and interstellar gas ...
*
Canes Venatici (constellation)
Canes Venatici ( ) is one of the 88 constellations designated by the International Astronomical Union (IAU). It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for 'hunting dogs', and ...
269
Year 269 ( CCLXIX) was a common year starting on Friday of the Julian calendar. At the time, it was known as the Year of the Consulship of Claudius and Paternus (or, less frequently, year 1022 ''Ab urbe condita''). The denomination 269 for this ...