NGC 4490, also known as the Cocoon Galaxy, is a

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, and generally affect both the motions of stars and interstellar gas within spiral galaxies ...

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 ...

William Herschel Frederick William Herschel (; german: Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline ...

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 A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

from Earth making it located in the local

universe The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the universe. ...

. 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 formatio ...

. NGC 4490 and NGC 4485 are collectively known in the

Atlas of Peculiar Galaxies The ''Atlas of Peculiar Galaxies'' is a 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 Institute of Technology. The ...

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 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 a G-type main-sequence star in the northern constellation of Canes Venatici. At an apparent visual magnitude of 4.25, it is the second-brigh ...

and with apparent visual magnitude 9.8, can be observed with 15x100 binoculars. It is a member of the

Herschel 400 Catalogue The Herschel 400 catalogue is a subset of William Herschel's original ''Catalogue of Nebulae and Clusters of Stars'', selected by Brenda F. Guzman (Branchett), Lydel Guzman, Paul Jones, James Morrison, Peggy Taylor and Sara Saey of the Ancient City ...

. It belongs to the

Canes II Group The Canes II Group or Canes Venatici II Group (CVn II Group) is a group of galaxies about 26.1 million light-years away from Earth. The group resides in the Local Supercluster. G. De Vaucouleurs, 1975. ''Nearby Groups of Galaxies'', ch. 5. the ne ...

Stellar stream

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 t ...

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. An example of a minor interaction is a satellite galaxy disturbing the primary galaxy's spiral arms. An example of a ...

. The stellar stream is made of bright knots and large

gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...

rich pockets. Young blue hot massive

stars A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth ma ...

are formed in this region.

Supernova

Two supernovae have been observed in NGC 4490: SN 1982F, a supernova of a unknown type and has a magnitude of16, and SN 2008ax, a type II supernova with a magnitude of 13.

Gallery

Result of a galactic crash.jpg, Extreme tidal forces have carved out the shapes and properties of NGC 4490.

References

External links

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SEDS
Canes II Group Canes Venatici Barred spiral galaxies Starburst galaxies 4490 07651 41333 Discoveries by William Herschel

269 Year 269 (Roman numerals, CCLXIX) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Claudius and Paternus (or, less frequently, year 102 ...

{{Spiral-galaxy-stub

Stellar stream

Supernova

Gallery

See also

References

External links