Messier 66 or
M66, also known as
NGC 3627, is an
intermediate spiral galaxy in the southern,
equatorial half of
Leo. It was discovered by French astronomer
Charles Messier[8] on 1 March 1780, who described it as "very long and very faint".
[9] This galaxy is a member of a small group of galaxies that includes
M65 and
NGC 3628, known as the
Leo Triplet, or the M66 Group.
[10] M65 and M66 make a popular pair for observers, being separated by only 20
′.
[9]M66 has a
morphological classification of SABb,
[5] indicating a spiral shape with a weak
bar feature and loosely wound
arms. The
isophotal axis ratio is 0.32, indicating that it is being viewed at an angle.
[5] M66 is receding from us with a heliocentric
radial velocity of 696.3±12.7 km/s.
[3] It lies 31
[4] million
light-years away and is about 95 thousand light-years across
[11] with striking
dust lanes and bright star clusters along sweeping spiral arms. As of 2018, five
supernovae have been observed in M66: SN 2016cok,
[12] 2009hd, 1997bs, 1989B, and 1973R.
[13] The one detected in 2016, SN 2016cok was discovered by the All-Sky Survey Automated Survey for Supernovae, and it has been categorized as a Type IIp supernova.
[14]Gravitational interaction from its past encounter with neighboring NGC 3628 has resulted in an extremely high central mass concentration; a high
molecular to
atomic mass ratio; and a resolved non-rotating clump of
H I material apparently removed from one of the
spiral arms. The latter feature shows up visually as an extremely prominent and unusual spiral arm and dust lane structures as originally noted in the
Atlas of Peculiar Galaxies.
[15] 
Comments