Arp 273

Arp 273 is a pair of interacting galaxies, 300 million light years away in the constellation Andromeda. It was first described in the Atlas of Peculiar Galaxies, compiled by Halton Arp in 1966.^[5] The larger of the spiral galaxies, known as UGC 1810, is about five times more massive than the smaller galaxy.^[6] It has a disc that is tidally distorted into a rose-like shape by the gravitational pull of the companion galaxy below it, known as UGC 1813. The smaller galaxy shows distinct signs of active star formation at its nucleus,^[7] and "it is thought that the smaller galaxy has actually passed through the larger one."^[8]

Arp 273
Image taken by the NASA/ESA Hubble Space Telescope shows Arp 273, a pair of interacting galaxies.
Observation data (J2000 epoch)
Constellation	Andromeda
Right ascension	02h 21m 28.703s[1]
Declination	+39° 22′ 32.65″[1]
Distance	300 million ly
Apparent magnitude (V)	13.7[2]
Characteristics
Type	SA(s)b pec[3] + SB(s)a pec[4]
Other designations
Z 523-28, Z 0218.4+3909, CGPG 0218.4+3909, ZW V 223, KPG 64a, UZC J022128.6+392231, 2MASX J02212870+3922326, Arp 273, UGC 1810, MCG +06-06-023, PGC 8961, VV 323, VV 323a[1]

The location of Arp 273 (circled in blue)

Arp 273 zoom sequence.

One supernova has been observed in UGC 1810: SN 1962R (type unknown, mag. 15.9) was discovered on plates taken at the Lick Observatory in December 1962, and presumed to be of type II.^[9][10][11]