Messier 66

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<ref name=SEDS/> on 1 March 1780, who described it as "very long and very faint".<ref name=OMeara2014/> 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.<ref name=Adam2018/> M65 and M66 are a common object for amateur astronomic observation, being separated by only Template:Val.<ref name=OMeara2014/>

M66 has a morphological classification of SABb,<ref name=Ann2015/> 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.<ref name=Ann2015/> M66 is receding from us with a heliocentric radial velocity of Template:Val.<ref name=Bosch2015/> It lies 31<ref name=Tully2016/> million light-years away and is about 95 thousand light-years across<ref>Per the small angle formula: 31 Mly × tan( 9.1Template:Prime ) = ~82 kly. diameter</ref> with striking dust lanes and bright star clusters along sweeping spiral arms.

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.<ref name="Zhangetal1993" />

Supernovae

Five supernovae have been observed in M66:

• SN 1973R (type II, mag. 14.5) was discovered by Leonida Rosino on 19 December 1973.<ref>{{#invoke:citation/CS1|citation

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• SN 1989B (type Ia, mag. 13) was discovered by Robert Evans on 30 January 1989.<ref>Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation

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• SN 1997bs (type uncertain, mag. 17) was discovered by the Lick Observatory Supernova Search (LOSS) on 15 April 1997.<ref>Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> This event was initially classified as a type IIn supernova, but more recent analysis suggests that it is instead either a luminous blue variable or a "gap" transient.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

• SN 2009hd (type II, mag. 15.8) was discovered by Libert (Berto) Monard on 2 July 2009.<ref>Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation

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• SN 2016cok (type IIP, mag. 16.6) was discovered by the All Sky Automated Survey for Supernovae on 28 May 2016.<ref name=Sutaria2016/><ref>{{#invoke:citation/CS1|citation

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Gallery

• Sig05-016.jpg

  Infrared false color view of M66 from the Spitzer Space Telescope

• Infrared false color view of M66 from the Jamess Webb Telescope.jpg

  Infrared false color view of M66 from the James Webb Space Telescope

• Messier 066 2MASS.jpg

  Messier 66 by 2MASS

• Messier 66 - NGC 3627 - GALEX.png

  An ultraviolet image of Messier 66 by GALEX

See also

• List of Messier objects

External links

• Spiral Galaxy M66
• Astronomy Picture of the Day – Unusual Spiral Galaxy M66 from Hubble – 2010 April 13
• Messier 66 Close Up, APOD June 13, 2024
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