Messier 69

Messier 69
M69 by Hubble Space Telescope; 3.5′ view Credit: NASA/STScI/WikiSky
Observation data (J2000 epoch)
Class	V[1]
Constellation	Sagittarius
Right ascension	18^h 31^m 23.10^s[2]
Declination	−32° 20′ 53.1″[2]
Distance	29.7 kly (9.1 kpc)
Apparent magnitude (V)	+8.31[3]
Apparent dimensions (V)	9′.8
Physical characteristics
Radius	42 ly[4]
Metallicity	$\begin{smallmatrix}\left[{Fe}/{H}\right]\end{smallmatrix}$ = –0.78[5] dex
Estimated age	13.06 Gyr[5]
Other designations	M69, NGC 6637, GCl 96[3]

Messier 69 (also known as M69 or NGC 6637) is a globular cluster in the constellation Sagittarius. It was discovered by Charles Messier on August 31, 1780, the same night he discovered M70. At the time, he was searching for an object described by LaCaille in 1751–2 and thought he had rediscovered it, but it is unclear if LaCaille actually described M69.

M69 is at a distance of about 29,700 light-years away from Earth and has a spatial radius of 42 light-years. It is a close neighbor of globular cluster M70, with 1,800 light-years separating the two objects; both of these clusters lie close to the galactic center. It is one of the most metal-rich globular clusters known.

Gallery

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  As globular clusters go, M69 is one of the most metal-rich on record.^[1]

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  Map showing location of M69 (Roberto Mura)

1. ^ "Cosmic riches". ESA/Hubble Picture of the Week. Retrieved 3 October 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 6637. Retrieved 2006-11-17.
4. distance × sin( diameter_angle / 2 ) = 42 ly. radius
5. 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

• Globular Cluster M69 @ SEDS Messier pages
• Messier 69, Galactic Globular Clusters Database page
• Messier 69 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Coordinates: 18^h 31^m 23.23^s, −32° 20′ 52.7″