Palomar 12

Palomar 12
Palomar 12 by Hubble Space Telescope, 3.36′ view
Observation data (J2000 epoch)
Class	XII
Constellation	Capricornus
Right ascension	21h 46m 38.84s
Declination	–21° 15′ 09.4″
Distance	63.6 ± 2.9 kly (19.50 ± 0.89 kpc)
Apparent magnitude (V)	11.99
Apparent dimensions (V)	17′.4
Physical characteristics
Mass	7004159000000000000♠1.59×104 M☉
Radius	162 ± 8 ly
Metallicity	${\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}}$ = –0.85dex
Estimated age	6.5 Gyr
Other designations	GCl 123
See also: Globular cluster, List of globular clusters

Palomar 12 is a globular cluster in the constellation Capricornus.

First discovered on the National Geographic Society – Palomar Observatory Sky Survey plates by Robert George Harrington and Fritz Zwicky, it was catalogued as a globular cluster. However Zwicky came to believe this was actually a nearby dwarf galaxy in the Local Group. It is a relatively young cluster, being about 30% younger than most of the globular clusters in the Milky Way. It is metal-rich with a metallicity of [Fe/H] ~= -0.8. It has an average luminosity distribution of M_v = -4.48.

Based on proper motion studies, this cluster was first suspected in 2000 to have been captured from the Sagittarius dwarf galaxy about 1.7 Ga ago. It is now generally believed to be a member of that galaxy. It is estimated to be 6.5 Gyr old.

Coordinates: 21^h 46^m 38.84^s, −21° 15′ 09.4″