Messier 70

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Messier 70
Messier 70 Hubble WikiSky.jpg
M70 from Hubble Space Telescope; 3.32′ view
Credit: NASA/STScI/WikiSky
Observation data (J2000 epoch)
Class V[1]
Constellation Sagittarius
Right ascension 18h 43m 12.76s[2]
Declination –32° 17′ 31.6″[3]
Distance 29.4 kly (9.0 kpc)[4]
Apparent magnitude (V) +9.06[3]
Apparent dimensions (V) 8′.0
Physical characteristics
Mass 1.79×105[4] M
Radius 34 ly[5]
Metallicity  = –1.35[6] dex
Estimated age 12.80 Gyr[6]
Other designations M70, NGC 6681, GCl 101[3]
See also: Globular cluster, List of globular clusters

Messier 70 (also known as M70 or NGC 6681) is a globular cluster in the constellation Sagittarius. It was discovered by Charles Messier in 1780.

M70 is at a distance of about 29,300 light years away from Earth and close to the Galactic Center. It is roughly the same size and luminosity as its neighbour in space, M69. Only two variable stars are known within this cluster.



  1. ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin (849): 11–14, Bibcode:1927BHarO.849...11S. 
  2. ^ Goldsbury, Ryan; et al. (December 2010), "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters", The Astronomical Journal, 140 (6): 1830–1837, arXiv:1008.2755Freely accessible, Bibcode:2010AJ....140.1830G, doi:10.1088/0004-6256/140/6/1830. 
  3. ^ a b c "NGC 6681". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-17. 
  4. ^ a b Boyles, J.; et al. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal, 742 (1): 51, arXiv:1108.4402Freely accessible, Bibcode:2011ApJ...742...51B, doi:10.1088/0004-637X/742/1/51. 
  5. ^ distance × sin( diameter_angle / 2 ) = 34 ly. radius
  6. ^ a b Forbes, Duncan A.; Bridges, Terry (May 2010), "Accreted versus in situ Milky Way globular clusters", Monthly Notices of the Royal Astronomical Society, 404 (3): 1203–1214, arXiv:1001.4289Freely accessible, Bibcode:2010MNRAS.404.1203F, doi:10.1111/j.1365-2966.2010.16373.x. 
  7. ^ "Tight and Bright". ESA/Hubble Picture of the Week. Retrieved 13 April 2012. 

External links[edit]

Coordinates: Sky map 18h 43m 12.64s, −32° 17′ 30.8″