Messier 66

Messier 66
A colour-composite image of M66
Observation data (J2000 epoch)
ConstellationLeo
Right ascension11h 20m 15.026s[1]
Declination+12° 59′ 28.64″[1]
Redshift0.002425±0.000010[2] (696.3±12.7 km/s)[3]
Distance31 Mly (9.6 Mpc)[4]
Apparent magnitude (V)8.9[2]
Characteristics
TypeSAB(s)b[5]
Apparent size (V)9.1′ × 4.2′[6]
Notable featuresGalaxy in the Leo Triplet
Other designations
Arp 16, NGC 3627, PGC 34695, UGC 6346[7]
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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 are a common object for amateur astronomic observation, 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.

Five supernovae have been observed in M66: SN 1973R (type IIP, mag. 14.5),[12] SN 1989B (type Ia, mag. 13),[13] SN 1997bs (Type IIn or LBV,[14] mag. 17),[15] SN 2009hd (Type II, mag. 15.8),[16] and SN 2016cok (Type IIP, mag. 16.6).[17][18][19] SN 2016cok was discovered by the All Sky Automated Survey for Supernovae.[20]

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.[21]

  1. ^ a b Cite error: The named reference Skrutskie2006 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference vaucoulerus1991 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Bosch2015 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Tully2016 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Ann2015 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference ned was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference simbad was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SEDS was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference OMeara2014 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Adam2018 was invoked but never defined (see the help page).
  11. ^ Per the small angle formula: 31 mly × tan( 9.1′ ) = ~82 kly. diameter
  12. ^ Transient Name Server entry for SN 1973R. Retrieved 24 March 2023.
  13. ^ Transient Name Server entry for SN 1989B. Retrieved 24 March 2023.
  14. ^ Van Dyk, Schuyler D.; Peng, Chien Y.; King, Jennifer Y.; Filippenko, Alexei V.; Richards, R. R.; Li, Weidong; Richmond, Michael W. (2000). "SN 1997bs in M66: Another Extragalactic η Carinae Analog?". Publications of the Astronomical Society of the Pacific. 112 (778): 1532–1541. arXiv:astro-ph/0009027. doi:10.1086/317727.
  15. ^ Transient Name Server entry for SN 1997bs. Retrieved 24 March 2023.
  16. ^ Transient Name Server entry for SN 2009hd. Retrieved 24 March 2023.
  17. ^ Cite error: The named reference Sutaria2016 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference CBAT was invoked but never defined (see the help page).
  19. ^ Transient Name Server entry for SN 2016cok. Retrieved 24 March 2023.
  20. ^ Lewis, Danny. "Spy Two Supernovae in June's Night Sky". Smithsonian. Retrieved 22 November 2019.
  21. ^ Cite error: The named reference Zhangetal1993 was invoked but never defined (see the help page).