Messier 70

Messier 70
M70 from Hubble Space Telescope; 3.32′ view Credit: NASA/STScI/WikiSky
Observation data (J2000 epoch)
Class	V[1]
Constellation	Sagittarius
Right ascension	18^h 43^m 12.76^s[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	1.79×10^5[4] M☉
Radius	34 ly[5]
Metallicity	$\begin{smallmatrix}\left[{Fe}/{H}\right]\end{smallmatrix}$ = –1.35[6] dex
Estimated age	12.80 Gyr[6]
Other designations	M70, NGC 6681, GCl 101[3]

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.

Gallery

• 

  Picture obtained with the Wide Field Camera of Hubble’s Advanced Camera for Surveys. The field of view is around 3.3 by 3.3 arcminutes.^[1]

• 

  Map showing location of M70 (Roberto Mura)

1. ^ "Tight and Bright". ESA/Hubble Picture of the Week. Retrieved 13 April 2012.

References

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:1008.2755, Bibcode:2010AJ....140.1830G, doi:10.1088/0004-6256/140/6/1830.
3. "SIMBAD Astronomical Object Database". Results for NGC 6681. Retrieved 2006-11-17.
4. Boyles, J.; et al. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal 742 (1): 51, arXiv:1108.4402, Bibcode:2011ApJ...742...51B, doi:10.1088/0004-637X/742/1/51.
5. distance × sin( diameter_angle / 2 ) = 34 ly. radius
6. 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:1001.4289, Bibcode:2010MNRAS.404.1203F, doi:10.1111/j.1365-2966.2010.16373.x.

External links

• Messier 70, SEDS Messier pages
• Messier 70, Galactic Globular Clusters Database page
• Messier 70 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

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