Editing Pegasus Dwarf Irregular Galaxy

{{Short description|Dwarf irregular galaxy in the constellation of Pegasus}}
{{Infobox Galaxy
| name = Pegasus Dwarf Irregular Galaxy
| image = Pegasus Dwarf-DDO216-starhopper.jpg
| caption = Pegasus Dwarf Irregular Galaxy (Pegasus Dwarf), DDO 216, UGC12613  <!-- Peg DIG on [[Digitized Sky Survey|DSS2]], 0.15° view (?)-->
| credit = 
| epoch = [[Epoch (astronomy)#Julian years and J2000|J2000]]
| type = dIrr/dSph<ref name=ned>{{cite web
  | title=NASA/IPAC Extragalactic Database
  | work=Results for PegDIG
  | url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=Pegasus+Dwarf#ObjNo1
  | accessdate=2007-03-15 }}</ref>{{Ref label|A|a|none}}
| ra = {{RA|23|28|36.2}}<ref name=ned/>
| dec = {{DEC|+14|44|35}}<ref name=ned/>
| dist_ly = 3.0 ± 0.1 [[light-year|Mly]] (920 ± 30 [[parsec|kpc]])<ref name=McConnachieetal2005/>
| z = −183 ± 0 km/[[second|s]]<ref name=ned/>
| appmag_v = 13.2<ref name=ned/>
| size_v = 5.0{{prime}} × 2.7{{prime}}<ref name=ned/>
| constellation name = [[Pegasus (constellation)|Pegasus]]
| notes =
| names = [[Uppsala General Catalogue|UGC]] 12613,<ref name=ned/> [[Principal Galaxies Catalogue|PGC]] 71538,<ref name=ned/> [[David Dunlap Observatory Catalogue|DDO]] 216,<ref name=ned/> Pegasus Dwarf,<ref name=ned/> PegDIG<ref name=ned/>
}}

The '''Pegasus Dwarf Irregular Galaxy''' (also known as '''Peg DIG''' or the '''Pegasus Dwarf''') is a [[Dwarf galaxy|dwarf]] [[irregular galaxy]] in the direction of the [[constellation]] [[Pegasus (constellation)|Pegasus]]. It was discovered by [[A. G. Wilson]] in the 1950s. The Pegasus Dwarf is a companion of the [[Andromeda Galaxy]] in the [[Local Group]].

==General information==

In 1975 Tully & Fisher determined that it was part of the Local Group.<ref name="Gallagerl998">{{cite journal
  | author=Gallager, J S.
  | title=A Wide Field Planetary Camera 2 Study of the Resolved Stellar Population of the Pegasus Dwarf Irregular Galaxy (DDO 216)
 | author2=Tolstoy, E.
  | author3=Dohm-Palmer, Robbie C.
  | author4=Skillman, E D.
  | author5=Cole, A A.
  | author6=Hoessel, J G.
  | author7=Saha, A.
  | author8=Mateo, M.
  | journal=The Astronomical Journal
  | date=1998
  | volume=115
  | issue=5
  | pages=1869–1889
  | doi=10.1086/300328
  | arxiv=astro-ph/9805284
 | bibcode=1998AJ....115.1869G
 | url=https://www.rug.nl/research/portal/en/publications/a-wide-field-planetary-camera-2-study-of-the-resolved-stellar-population-of-the-pegasus-dwarf-irregular-galaxy-ddo-216(9e84a3d9-98a1-45ad-9bab-3d703d3b0eba).html
 | hdl=11370/9e84a3d9-98a1-45ad-9bab-3d703d3b0eba
  | s2cid=119497686
 | hdl-access=free
  }}</ref>
The [[metallicity]] and the related distance estimate has been subject to discussions in the scientific literature, with varying results; however, recently, by use of the [[tip of the red-giant branch]], a distance within 10% error was achieved in 2000<ref name="Karachentsevetal2004">{{cite journal
  | author=Karachentsev, Igor D.
  | author2=Karachentseva, Valentina E.
  | author3=Huchtmeier, Walter K.
  | author4=Makarov, Dmitry I.
  | title=A Catalog of Neighboring Galaxies
  | journal=The Astronomical Journal
  | date=2004
  | volume=127
  | issue=4
  | pages=2031–2068
  | bibcode=2004AJ....127.2031K
  | doi=10.1086/382905
| doi-access=free
  }}</ref><ref name="van den Bergh2000">{{cite book
  | last=van den Bergh
  | first=Sidney
  | authorlink=Sidney van den Bergh
  | title=The Galaxies of the Local Group
  | date=2000
  | publisher=[[Cambridge University Press]]
  | location=Cambridge, UK
  | isbn=0-521-65181-6
  | bibcode=2000glg..book.....V
 }}</ref>
and then improved to 3% in 2005.<ref name="McConnachieetal2005">{{cite journal
  | author=McConnachie, A. W.
  | author2=Irwin, M. J.
  | author3=Ferguson, A. M. N.
  | author4=Ibata, R. A.
  | author5=Lewis, G. F.
  | author6=Tanvir, N.
  | title=Distances and metallicities for 17 Local Group galaxies
  | journal=[[Monthly Notices of the Royal Astronomical Society]]
  | date=2005
  | volume=356
  | issue=4
  | pages=979–997
  | bibcode=2005MNRAS.356..979M   | doi=10.1111/j.1365-2966.2004.08514.x
| doi-access=free
 |arxiv = astro-ph/0410489 }}</ref>
[[Image:Local Group.svg|thumb|500px|left|Location of '''Pegasus Dwarf''' in the [[Local Group]].]]
{{clear}}

==In popular culture==
The [[science fiction]] television series ''[[Stargate Atlantis]]'' takes place in the "Pegasus galaxy" and has shown images of an irregular galaxy. However, the franchise has not explicitly stated if it is the Irregular, [[Pegasus Dwarf Spheroidal Galaxy|Spheroidal]], or an entirely fictional location,<ref name="The Return">"[[The Return (Stargate Atlantis)|The Return]]" (''[[Stargate Atlantis]]'')</ref> but since the series claimed the Pegasus galaxy to be 3 million light years away, it is likely the irregular one.

==See also==
* [[Pegasus Dwarf Spheroidal Galaxy]] (Peg dSph)
* [[Pegasus Galaxy (Stargate)|Pegasus galaxy]], the [[Stargate Atlantis]] fictional location.

==Notes==
{{refbegin}}
<ol type="a">
<li>{{Note label|A|a|none}}NED gives the galaxy classification as both dIrr and dSph, which means that it is a transitory between dwarf irregular and dwarf spheroidal.  It is noted as transitory in Cole et al. 1999.<ref name="Coleetal1999">{{cite journal
  | author=Cole, Andrew A.
  | author2=Tolstoy, Eline
  | author3=Gallagher, John S., III
  | author4=Hoessel, John G.
  | author5=Mould, Jeremy R.
  | author6=Holtzman, Jon A.
  | author7=Saha, Abhijit
  | author8=Ballester, Gilda E.
  | author9=Burrows, Christopher J.
  | author10=Clarke, John T.
  | author11=Crisp, David
  | author12=Griffiths, Richard E.
  | author13=Grillmair, Carl J.
  | author14=Hester, Jeff J.
  | author15=Krist, John E.
  | author16=Meadows, Vikki
  | author17=Scowen, Paul A.
  | author18=Stapelfeldt, Karl R.
  | author19=Trauger, John T.
  | author20=Watson, Alan M.
  | author21=Westphal, James R.
  | title=Stellar Populations at the Center of IC 1613
  | journal=The Astronomical Journal
  | date=1999
  | volume=118
  | issue=4
  | pages=1657–1670
  | bibcode=1999AJ....118.1657C
  | doi=10.1086/301042
|arxiv = astro-ph/9905350 | s2cid=17566586
 }}</ref></li>
</ol>
{{refend}}

==References==
{{reflist}}

==External links==
*{{WikiSky|PGC 71538|z=10}}
{{Sky|23|28|36.2|+|14|44|35|3000000}}

[[Category:Dwarf irregular galaxies]]
[[Category:Local Group]]
[[Category:Andromeda Subgroup]]
[[Category:Pegasus (constellation)]]
[[Category:UGC objects|12613]]
[[Category:Principal Galaxies Catalogue objects|71538]]