Palomar 12 | |
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![]() Palomar 12 by
Hubble Space Telescope, 3.36′ view | |
Observation data ( J2000 epoch) | |
Class | XII |
Constellation | Capricornus |
Right ascension | 21h 46m 38.84s [1] |
Declination | –21° 15′ 09.4″ [1] |
Distance | 63.6 ± 2.9 kly (19.50 ± 0.89 kpc) [2] |
Apparent magnitude (V) | 11.99 |
Apparent dimensions (V) | 17.4′ |
Physical characteristics | |
Mass | 1.59×104 [3] M☉ |
Radius | 162 ± 8 ly [4] |
Metallicity | = –0.85 [3] dex |
Estimated age | 6.5 Gyr [5] |
Notable features | Probably extragalactic |
Other designations | GCl 123 [6] |
Palomar 12 is a globular cluster in the constellation Capricornus, and is a member of the Palomar Globular Clusters group.
First discovered on the National Geographic Society – Palomar Observatory Sky Survey plates by Robert George Harrington and Fritz Zwicky, [7] it was initially catalogued as a globular cluster; however, Zwicky came to believe it 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]
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 [1] |
Declination | –21° 15′ 09.4″ [1] |
Distance | 63.6 ± 2.9 kly (19.50 ± 0.89 kpc) [2] |
Apparent magnitude (V) | 11.99 |
Apparent dimensions (V) | 17.4′ |
Physical characteristics | |
Mass | 1.59×104 [3] M☉ |
Radius | 162 ± 8 ly [4] |
Metallicity | = –0.85 [3] dex |
Estimated age | 6.5 Gyr [5] |
Notable features | Probably extragalactic |
Other designations | GCl 123 [6] |
Palomar 12 is a globular cluster in the constellation Capricornus, and is a member of the Palomar Globular Clusters group.
First discovered on the National Geographic Society – Palomar Observatory Sky Survey plates by Robert George Harrington and Fritz Zwicky, [7] it was initially catalogued as a globular cluster; however, Zwicky came to believe it 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]