Messier 85 (NGC 4382) is a lenticular galaxy in Coma Berenices. It is one of the brighter members of the Coma-Virgo Cluster. M 85 was discovered in 1781 by Pierre Mechain, and confirmed the same year by Charles Messier.
M 85 is of visual magnitude 9.1, and appears 7.1' x 5.2' in size. Its large, bright oval core is embedded in a much fainter halo extending north to south. Larger instruments show that M 85 has a brilliant nucleus within a 2' x 1.75' core, embedded in a faint halo.
The type I supernova 1960R was discovered in M 85 in 1960, and reached magnitude 11.7. Supernova hunters should take care not to be fooled by the foreground star SSE of this galaxy's nucleus!
Messier 85 is 60 million light years away, and estimated to be 125,000 light years across. It is one of the largest and brightest Coma-Virgo galaxies. Its absolute magnitude is -22.5, a luminosity of 83 billion Suns, and has a total mass of around 100 billion Suns.
M 85 is a luminous lenticular (S0) galaxy; in many respects it seems to be a twin of M84. It seems to consist of an old yellow stellar population only.
Near M 85 are several companion galaxies: NGC 4394, which appears as a hazy "star" of magnitude 11.2 about 8' to the east; IC 3292, a very faint companion 8.5' to the west; and a small elliptical galaxy called MCG 3-32-38. As M 85 and NGC 4394 galaxies are both receding at about 700 km/sec, they may form a physical pair.