Editing Canis Major Overdensity (section)

{{Short description|Disputed galaxy located near the constellation Canis Major}}
{{Use dmy dates|date=May 2020}}
{{Infobox galaxy
| image = 
   {{Location mark
     | image=Canis Major constellation map.svg
     | float=center | width=240 | position=right
     | mark=Red circle.svg | mark_width=10 | mark_link= 
     | x%=17 | y%=75
   }}
| caption=Location of the Canis Major Overdensity (red circle)
 | name = Canis Major Overdensity
| epoch = [[Epoch (astronomy)#Julian years and J2000|J2000]]
| type = Irr
| ra = {{RA|07|12|35.0}}<ref name="ned">{{Cite web |title=NASA/IPAC Extragalactic Database |url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=Canis+Major+Dwarf#ObjNo1 |website=Results for Canis Major Dwarf |access-date=16 March 2007}}</ref>
| dec = {{DEC|-27|40|00}}<ref name="ned" />
| dist_ly = {{val|25000|fmt=commas}} [[light-year|ly]]
| stars = 1 billion (1×10<sup>9</sup>)
| z = 
| appmag_v = 
| size_v = 12 [[degree (angle)|degrees]] × 12 degrees
| constellation name = [[Canis Major]]
| names = CMa Dwarf,<ref name="ned" /> PGC 5065047
}}

The '''Canis Major Overdensity''' (''CMa Overdensity'') or '''Canis Major Dwarf Galaxy''' (''CMa Dwarf'') is a disputed [[Irregular galaxy|dwarf irregular galaxy]] in the [[Local Group]], located in the same part of the sky as the [[constellation]] [[Canis Major]].

The supposed small [[galaxy]] contains a relatively high percentage of [[red giant]]s and is thought to contain an estimated one billion stars in all.

At the time of its announcement, the Canis Major Dwarf Galaxy was classified as an irregular galaxy and was thought to be the closest neighboring galaxy to the Earth's location in the [[Milky Way]], located about {{convert|25000|ly|kpc|abbr=off|lk=off}} away from the [[Solar System]]<ref name="Can">{{Cite web |title=Astronomers find nearest galaxy to the Milky Way |url=http://astro.u-strasbg.fr/images_ri/canm-e.html |archive-url=https://web.archive.org/web/20080527020725/http://astro.u-strasbg.fr/images_ri/canm-e.html |archive-date=27 May 2008 |access-date=24 September 2009}}</ref> and {{convert|42000|ly|kpc|abbr=on|lk=on}} from the [[Galactic Center]]. It has a roughly elliptical shape and is thought to contain as many stars as the [[Sagittarius Dwarf Elliptical Galaxy]], the previous contender for closest galaxy to Earth, though later studies disputed this conclusion.