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]
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.[5]
^Wild, P. (1982). "Probable Supernova in NGC 4490". International Astronomical Union Circular (3689): 1. Bibcode:1982IAUC.3689....1W.
^"SN1982F". Transient Name Server. IAU. Retrieved 5 December 2024.
^Mostardi, R.; Li, W.; Filippenko, A. V. (2008). "Possible Supernova in NGC 4490". Central Bureau Electronic Telegrams. 1280: 1. Bibcode:2008CBET.1280....1M.
^Nakano, S. (2008). "Supernova 2008ax in NGC 4490". Central Bureau Electronic Telegrams. 1286: 1. Bibcode:2008CBET.1286....1N.