View source for NGC 2419

{{short description|Globular cluster in the constellation Lynx}}
{{Infobox globular cluster
| name = NGC 2419
| image = Caldwell 25.jpg
| caption = NGC 2419 by [[Hubble Space Telescope|HST]]<ref>{{cite web |title=The two mysterious populations of NGC 2419 |url=https://spacetelescope.org/images/potw1908a/ |website=www.spacetelescope.org |access-date=25 February 2019 |language=en}}</ref>
| credit =
| epoch = [[J2000]]
| class = VII<ref name=hcob849_11/>
| constellation = [[Lynx (constellation)|Lynx]]
| ra = {{RA|07|38|08.51}}<ref name="simbad">{{cite simbad
  | title=NGC 2419
  | access-date=2006-11-17}}</ref>
| dec = {{DEC|+38|52|54.9}}<ref name="simbad" />
| dist_ly = 275 [[light year|kly]] <small>(from the [[Sun]])</small><br>300 kly <small>(from the [[Galactic Center|GC]])</small>
| dist_pc = 84.2 [[parsec|kpc]] <small>([[Sun]])</small><br>91.5 kpc <small>(GC)</small><ref name="harris">{{cite journal| author = Harris, W.E.| date = 1996| title = A Catalog of Parameters for Globular Clusters in the Milky Way| journal = The Astronomical Journal| volume = 112| pages = 1487| url = http://physwww.physics.mcmaster.ca/%7Eharris/mwgc.dat| doi = 10.1086/118116| bibcode=1996AJ....112.1487H| url-access = subscription}}</ref>
| appmag_v = +9.06<ref name="simbad" />
| size_v = 6{{prime}}
| mass_kg = 
| mass_msol = 9 x 10^5
| radius_ly = 260 ly<ref>distance × sin( diameter_angle / 2 ) = 260 ly. radius</ref>
| v_hb = 20.45<ref name="harris" />
| metal_fe = –2.14<ref name=mnras404_3_1203/>
| age = 12.3&nbsp;[[Gigayear|Gyr]]<ref name=mnras404_3_1203/>
| notes = 
| names = GCl 112,<ref name="simbad" /> [[Caldwell catalogue|Caldwell]]&nbsp;25
}}
'''NGC 2419''' (also known as '''[[Caldwell_catalogue|Caldwell 25]]''') is a [[globular cluster]] in the constellation [[Lynx (constellation)|Lynx]]. It was discovered by [[William Herschel]] on December 31, 1788.<ref>http://messier.seds.org/xtra/ngc/n2419.html NGC 4189 at SEDS</ref> NGC 2419 is at a distance of about 300,000 [[light year]]s from the [[Solar System]] and at the same distance from the [[Galactic Center]].

NGC 2419 bears the nickname "the Intergalactic Wanderer," which was bestowed when it was erroneously thought not to be in orbit around the [[Milky Way]].  Its orbit takes it farther away from the galactic center than the [[Magellanic 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.<ref name = "ferris">Ferris, Timothy. ''Seeing in the Dark''. 2002. p. 244</ref>

The cluster is dim in comparison to more famous globular clusters such as [[Messier 13|M13]]. 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 an [[absolute magnitude]] of −9.42<ref name="harris" /> and being 900,000 times more massive than the Sun.<ref name="Baumgardt2009">{{cite journal
    | author=Baumgardt, H. |display-authors=4  | author2=Côté, P. | author3=Hilker, M. | author4=Rejkuba, M. | author5=Mieske, S. | author6=Djorgovski, S. G. | author7=Stetson, Peter
    | title=The velocity dispersion and mass-to-light ratio of the remote halo globular cluster NGC2419
    | journal=[[Monthly Notices of the Royal Astronomical Society]]
    | date=2009
    | volume=396
    | issue=4
    | pages=2051–2060
    | bibcode=2009MNRAS.396.2051B|arxiv = 0904.3329 |doi = 10.1111/j.1365-2966.2009.14932.x |doi-access=free |s2cid=7956224 }}</ref>

It was proposed that NGC 2419 could be, as [[Omega Centauri]], the remnant of a [[dwarf spheroidal galaxy]] disrupted and accreted by the Milky Way.<ref name="vandenBergh2004">{{cite journal
    | author=van den Bergh, Sidney | author2=Mackey, A. D.
    | title=Globular clusters and the formation of the outer Galactic halo
    | journal=Monthly Notices of the Royal Astronomical Society
    | date=2004
    | volume=354
    | issue=3
    | pages=713–719
    | bibcode=2004MNRAS.354..713V|arxiv = astro-ph/0407346 |doi = 10.1111/j.1365-2966.2004.08228.x | doi-access=free
 | s2cid=15407602
 }}</ref> However, that hypothesis has been disputed.<ref name="Ripepi2007">{{cite journal
    | author=RIPEPI V. |display-authors=4  | author2=CLEMENTINI G. | author3=DI CRISCIENZO M. | author4=GRECO C. | author5=DALL'ORA M. | author6=FEDERICI L. | author7=DI FABRIZIO L. | author8=MUSELLA I. | author9=MARCONI M. | author10=BALDACCI L. | author11=MAIO M.
    | title=On the remote galactic globular cluster NGC 2419.
    | journal=The Astrophysical Journal
    | date=2007
    | volume=667
    |issue=1  | pages=L61–L64
    | bibcode=2007ApJ...667L..61R|arxiv = 0705.0966 |doi = 10.1086/522000 |s2cid=15186576 }}</ref>

Astronomer Leos Ondra has noted that NGC 2419 would be the "best and brightest" for any observers in the [[Andromeda Galaxy]], looking for globular clusters in our galaxy since it lies outside the obscuring density of the main disk.<ref name = "ferris"/> This is analogous to the way the cluster [[Mayall II|G1]] 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.<ref>{{Cite web|last=|date=February 2019|title=The two mysterious populations of NGC 2419|url=https://www.spacetelescope.org/images/potw1908a/|access-date=2021-02-25|website=www.spacetelescope.org|language=en}}</ref>

==Gallery==
<gallery>
NGC 2419.jpg|NGC 2419 – wide field view
NGC 2419 Hubble WikiSky.jpg|Center of NGC 2419 ([[Hubble Space Telescope]])
</gallery>

==References==
{{reflist|refs=

<ref name=hcob849_11>{{citation | last1=Shapley | first1=Harlow | last2=Sawyer | first2=Helen B. | title=A Classification of Globular Clusters | journal=Harvard College Observatory Bulletin | volume=849 | issue=849 | pages=11–14 |date=August 1927 | bibcode=1927BHarO.849...11S | postscript=. }}</ref>

<ref name=mnras404_3_1203>{{citation | last1=Forbes | first1=Duncan A. | last2=Bridges | first2=Terry | title=Accreted versus in situ Milky Way globular clusters | journal=Monthly Notices of the Royal Astronomical Society | volume=404 | issue=3 | pages=1203–1214 |date=May 2010 | doi=10.1111/j.1365-2966.2010.16373.x | doi-access=free | bibcode=2010MNRAS.404.1203F | postscript=. |arxiv = 1001.4289 | s2cid=51825384 }}</ref>

}}

==External links==
{{commons category|NGC 2419}}
* [http://messier.seds.org/xtra/ngc/n2419.html SEDS] – NGC 2419
* [http://www.perseus.gr/Astro-DSO-NGC-2419.htm perseus.gr] – NGC 2419 in a LRGB CCD image based on 2 hrs total exposure
* [http://antwrp.gsfc.nasa.gov/apod/ap090123.html APOD (2009-01-23)] – NGC 2419
* {{WikiSky}}
* {{CelestialRefEx}}

{{Sky|07|38|08.51|+|38|52|54.9|275000}}
{{Catalogs|NGC=2419|C=25}}
{{Caldwell catalogue}}
{{Ngc25}}
{{Lynx (constellation)}}

[[Category:Globular clusters]]
[[Category:Lynx (constellation)]]
[[Category:NGC objects|2419]]
[[Category:Caldwell objects|025b]]
[[Category:Astronomical objects discovered in 1788]]