HCG 2 is one of the compact groups of galaxies in the Hickson Compact Group of galaxies. It is located in Pisces east of HD 2679 and is 192 million light-years away. HCG 2 is one of a hundred such groups identified by a systematic search of the Palomar Observatory Sky Survey red prints in 1982 by Paul Hickson. Hickson Compact Group 2 has a velocity dispersion of 55 km/s and the crossing time (H0tc) of HCG 2 is 0.087. HCG 2 is classified as a Gas Rich Group, which studies show that UGC 00312 has many bright star forming regions, whereas MCG +01-02-018 (Mrk 552) is a compact and luminous galaxy.
Properties HCG 2A is the brightest member of this group, which has a Blue Minus Red (B-R) of 0.88, and a Corrected Total Blue Magnitude (B_TC) of 13.35, suggesting that it is a galaxy high in Star Birth and Interstellar Gas Reservoirs. While HCG 2A is the brightest, HCG 2D is dimmest and furthest galaxy, which has a B-R of 1.54, B_TC of 15.74, a distance and a velocity of 1,009.8 Million Light Years, 21340 km/s respectively, revealing it is a galaxy in the deep universe and is likelihood dominated by ageing and cooling stars. A study suggests that the Spiral fraction is 100%, indicating all 4 galaxies in this group are spirals. In another study, HCG 2A, 2B and 2C have a disturbed morphology, hinting to astronomers that it is gravitationally interacting with other galaxies and possibly merging. For HCG 2A, it has a tail, and is a possible strong Infrared source, while HCG 2B, is a strong Infrared source, indicating a high amount star formation and stellar nurseries. Another study shows that in the background field of HCG 2, there are 18 foreground stars and 27 foreground galaxies that are in a significant distance away from the group.
Members HCG 2 consists of four member galaxies. Their names and basic properties are listed below.
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