| NGC 2419 | |
|---|---|
 | |
| Observation data (J2000epoch) | |
| Class | VII[2] |
| Constellation | Lynx |
| Right ascension | 07h 38m 08.51s[3] |
| Declination | +38° 52′ 54.9″[3] |
| Distance | 275kly(from theSun) 300 kly(from theGC) (84.2kpc(Sun) 91.5 kpc(GC)[4]) |
| Apparent magnitude(V) | +9.06[3] |
| Apparent dimensions(V) | 6′ |
| Physical characteristics | |
| Mass | 9 x 10^5 M☉ |
| Radius | 260 ly[5] |
| VHB | 20.45[4] |
| Metallicity | = –2.14[6]dex |
| Estimated age | 12.3 Gyr[6] |
| Other designations | GCl 112,[3]Caldwell 25 |
| See also:Globular cluster,List of globular clusters | |
NGC 2419 (also known asCaldwell 25) is aglobular cluster in the constellationLynx. It was discovered byWilliam Herschel on December 31, 1788.[7] NGC 2419 is at a distance of about 300,000light years from theSolar System and at the same distance from theGalactic Center.
NGC 2419 bears the nickname "the Intergalactic Wanderer," which was bestowed when it was erroneously thought not to be in orbit around theMilky Way. Its orbit takes it farther away from the galactic center than theMagellanic Clouds, but it can (with qualifications) be considered as part of the Milky Way. At this great distance it takes three billion years to make one trip around the galaxy.[8]
The cluster is dim in comparison to more famous globular clusters such asM13. Nonetheless, NGC 2419 is a 9th magnitude object and is readily viewed, in good sky conditions, with good quality telescopes as small as 102mm (four inches) in aperture. Intrinsically it is one of the brightest and most massive globular clusters of our galaxy, having anabsolute magnitude of −9.42[4] and being 900,000 times more massive than the Sun.[9]
It was proposed that NGC 2419 could be, asOmega Centauri, the remnant of adwarf spheroidal galaxy disrupted and accreted by the Milky Way.[10] However, that hypothesis has been disputed.[11]
Astronomer Leos Ondra has noted that NGC 2419 would be the "best and brightest" for any observers in theAndromeda Galaxy, looking for globular clusters in our galaxy since it lies outside the obscuring density of the main disk.[8] This is analogous to the way the clusterG1 can be seen orbiting outside of the Andromeda Galaxy from Earth.
It was found to be composed of two different populations, one being more helium-rich than the other, which does not fit the current model for globular cluster formation (which leads to a very homogeneous population in the cluster). This raises new questions on how this globular cluster was formed.[12]
