# Palomar 12

Palomar 12
Palomar 12 by Hubble Space Telescope, 3.36′ view
Observation data (J2000 epoch)
ClassXII
ConstellationCapricornus
Right ascension21h 46m 38.84s[1]
Declination–21° 15′ 09.4″[1]
Distance63.6 ± 2.9 kly (19.50 ± 0.89 kpc)[2]
Apparent magnitude (V)11.99
Apparent dimensions (V)17′.4
Physical characteristics
Mass1.59×104[3] M
Radius162 ± 8 ly[4]
Metallicity${\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}}$ = –0.85[3] dex
Estimated age6.5 Gyr[5]
Notable featuresProbably extragalactic
Other designationsGCl 123[6]
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,[7] 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.[2] It is metal-rich with a metallicity of [Fe/H] ≈ −0.8.[5] It has an average luminosity distribution of Mv = −4.48.[8]

Based on proper motion studies, this cluster was first suspected in 2000 to have been captured from the Sagittarius Dwarf Elliptical Galaxy (SagDEG) about 1.7 Ga ago.[9] It is now generally believed to have originated in that galaxy and is associated with the Sagittarius Stream.[5] It is estimated to be 6.5 Gyr old.[5]