NGC 6352

NGC 6352 (also known as Caldwell 81) is a globular cluster of stars in the southern constellation of Ara, located approximately 18.3 kly^[3] from the Sun. It was discovered by Scottish astronomer James Dunlop on May 14, 1826.^[10] The cluster has a Shapley–Sawyer Concentration Class of XI:.^[1] A telescope with a 15 cm (5.9 in) aperture is required to resolve the stars within this loose cluster.^[4]

NGC 6352
Observation data (J2000 epoch)
Class	XI:[1]
Constellation	Ara
Right ascension	17h 25m 29.11s[2]
Declination	–48° 25′ 19.8″[2]
Distance	18.3 kly (5.6 kpc)[3]
Apparent magnitude (V)	+7.8[4]
Apparent dimensions (V)	7.1′[5]
Physical characteristics
Mass	3.7×104[6] M☉
Tidal radius	10.5″[7]
Metallicity	${\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}}$ = –0.70[8] dex
Estimated age	12.67 Gyr[8]
Other designations	Caldwell 81, Cr 328, NGC 6352[9]
See also: Globular cluster, List of globular clusters

This cluster is about 12.67^[8] billion years old with two distinct stellar populations; the second generation is only around 10 million years younger than the first.^[3] It lies approximately 13 kly (4 kpc) from the Galactic Center and 1.6 kly (0.5 kpc) from the galactic plane.^[11] The orbital motion of this cluster through the Milky Way suggests it is a member of the bulge or disk population.^[12] It is relatively metal-rich for an object of this class,^[3] having a metallicity of –0.70.^[8] The core radius is 49.8″^[3] and the tidal radius is 10.5″.^[7]