View source for IC 1613

{{Short description|Irregular dwarf galaxy in the constellation Cetus}}
{{Infobox Galaxy
| image = Dwarf galaxy IC 1613.jpg
| image_scale = 
| caption = IC 1613 captured with the [[Very Large Telescope|VLT]]'s OmegaCAM.<ref>{{cite web|title=The Milky Way's Clean and Tidy Galactic Neighbour|url=http://www.eso.org/public/news/eso1603/|access-date=29 January 2016}}</ref>
| name = [[Index Catalogue|IC]] 1613
| group_cluster = [[Local Group]]
| epoch = [[J2000]]
| type = IB(s)m<ref name="ned">{{cite web
  | title=NASA/IPAC Extragalactic Database
  | work=Results for IC 1613
  | url=http://nedwww.ipac.caltech.edu/
  | access-date=2006-11-29 }}</ref>
| mass={{val|1.1|0.2|e=8}}<ref name="Skillman2014"/>
| ra = {{RA|01|04|47.8}}<ref name="ned" />
| dec = {{DEC|+02|07|04}}<ref name="ned" />
| dist_ly = {{val|2.38|0.07|ul=Mly}} ({{val|730|20|ul=kpc}})<ref name="karachentsevetal2004">{{cite journal
  |author1=I. D. Karachentsev |author2=V. E. Karachentseva |author3=W. K. Hutchmeier |author4=D. I. Makarov | title=A Catalog of Neighboring Galaxies
  | journal=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="Karachentsevetal2006">{{cite journal
  |author1=Karachentsev, I. D. |author2=Kashibadze, O. G. | title=Masses of the local group and of the M81 group estimated from distortions in the local velocity field
  | journal=Astrophysics
  | date=2006
  | volume=49
  | issue=1
  | pages=3–18
  | bibcode=2006Ap.....49....3K
  | doi=10.1007/s10511-006-0002-6 |s2cid=120973010 }}</ref>
| z = {{val|-234|1|ul=km/s}}<ref name="ned" />
| appmag_v = 9.9<ref name="ned" />
| absmag_v = −15.2<ref name="Skillman2014">{{cite journal |last1=Skillman |first1=Evan D. |last2=Hidalgo |first2=Sebastian L. |last3=Weisz |first3=Daniel R. |last4=Monelli |first4=Matteo |last5=Gallart |first5=Carme |last6=Aparicio |first6=Antonio |last7=Bernard |first7=Edouard J. |last8=Boylan-Kolchin |first8=Michael |last9=Cassisi |first9=Santi |last10=Cole |first10=Andrew A. |last11=Dolphin |first11=Andrew E. |last12=Ferguson |first12=Henry C. |last13=Mayer |first13=Lucio |last14=Navarro |first14=Julio F. |last15=Stetson |first15=Peter B. |last16=Tolstoy |first16=Eline |title=The ACS LCID project. X. The star formation history of IC 1613: revisiting the over-cooling problem |journal=The Astrophysical Journal |date=15 April 2014 |volume=786 |issue=1 |pages=44 |doi=10.1088/0004-637X/786/1/44|arxiv=1403.4609 |bibcode=2014ApJ...786...44S }}</ref>
| size_v = {{val|16.2|ul='}} × {{val|14.5|u='}}<ref name="ned" />
| constellation name = [[Cetus]]
| notes = 
| names = [[Uppsala General Catalogue|UGC]] 668,<ref name="ned" /> [[David Dunlap Observatory Catalogue|DDO]] 8,<ref name="ned" /> [[Principal Galaxies Catalogue|PGC]] 3844,<ref name="ned" /> [[Caldwell catalogue|Caldwell]]&nbsp;51
}}

[[File:The sky around the dwarf galaxy IC 1613.jpg|thumb|left|The sky around IC 1613, with [[26 Ceti]] towards the bottom of the frame (south) and [[29 Ceti]] to the left (east)]]
'''IC 1613''' (also known as '''Caldwell 51''') is an [[irregular galaxy|irregular]] [[dwarf galaxy]] located on the outskirts of the [[Local Group|Local group]] around 730 kiloparsecs from [[Earth]] in the [[constellation]] of [[Cetus]] near the star [[26 Ceti]].<ref>{{Cite journal|last1=Cole|first1=Andrew A.|last2=Tolstoy|first2=Eline|last3=Gallagher III|first3=John S.|last4=Hoessel|first4=John G.|last5=Mould|first5=Jeremy R.|last6=Holtzman|first6=Jon A.|last7=Saha|first7=Abhijit|last8=Ballester|first8=Gilda E.|last9=Burrows|first9=Christopher J.|last10=Clarke|first10=John T.|last11=Crisp|first11=David|date=October 1999|title=Stellar Populations at the Center of IC 1613|url=http://stacks.iop.org/1538-3881/118/i=4/a=1657|journal=The Astronomical Journal|volume=118|issue=4|pages=1657–1670|doi=10.1086/301042|bibcode=1999AJ....118.1657C|arxiv=astro-ph/9905350|hdl=11370/f890fe5e-7780-4296-b2e0-a1e6e4b51f11|s2cid=17566586}}</ref> It has a low mass with its mass only being around 10^8 solar masses.<ref>{{Cite journal |last1=Zheng |first1=Yong |last2=Emerick |first2=Andrew |last3=Putman |first3=Mary E. |last4=Werk |first4=Jessica K. |last5=Kirby |first5=Evan N. |last6=Peek |first6=Joshua |date=December 2020 |title=Characterizing the Circumgalactic Medium of the Lowest-mass Galaxies: A Case Study of IC 1613 |journal=The Astrophysical Journal |language=en |volume=905 |issue=2 |pages=133 |doi=10.3847/1538-4357/abc875 |doi-access=free |arxiv=2010.15645 |bibcode=2020ApJ...905..133Z |issn=0004-637X}}</ref> It has played an important role in the calibration of the [[Cepheid variable]] [[period-luminosity relation]] for estimating distances.<ref>{{Cite journal |last1=Cole |first1=Andrew A. |last2=Tolstoy |first2=Eline |last3=Gallagher III |first3=John S. |last4=Hoessel |first4=John G. |last5=Mould |first5=Jeremy R. |last6=Holtzman |first6=Jon A. |last7=Saha |first7=Abhijit |last8=Ballester |first8=Gilda E. |last9=Burrows |first9=Christopher J. |last10=Clarke |first10=John T. |last11=Crisp |first11=David |date=October 1999 |title=Stellar Populations at the Center of IC 1613 |url=http://stacks.iop.org/1538-3881/118/i=4/a=1657 |journal=The Astronomical Journal |volume=118 |issue=4 |pages=1657–1670 |arxiv=astro-ph/9905350 |bibcode=1999AJ....118.1657C |doi=10.1086/301042 |doi-access=free |hdl=11370/f890fe5e-7780-4296-b2e0-a1e6e4b51f11}}</ref> Other than the [[Magellanic Clouds]], it is one of the few Local Group dwarf irregular galaxy where [[RR Lyrae-type variable]]s have been observed; this factor, along with an unusually low abundance of [[interstellar dust]] both within IC 1613 and along the line of sight enable especially accurate distance estimates.<ref name="Coleetal1999" /><ref>{{Cite web |title=The Milky Way's Clean and Tidy Galactic Neighbour |url=https://www.eso.org/public/news/eso1603/}}</ref> IC 1613 was discovered in 1906 by [[Max Wolf]],<ref>{{Cite journal|last1=Cole|first1=Andrew A.|last2=Tolstoy|first2=Eline|last3=Gallagher III|first3=John S.|last4=Hoessel|first4=John G.|last5=Mould|first5=Jeremy R.|last6=Holtzman|first6=Jon A.|last7=Saha|first7=Abhijit|last8=Ballester|first8=Gilda E.|last9=Burrows|first9=Christopher J.|last10=Clarke|first10=John T.|last11=Crisp|first11=David|date=October 1999|title=Stellar Populations at the Center of IC 1613|url=http://stacks.iop.org/1538-3881/118/i=4/a=1657|journal=The Astronomical Journal|volume=118|issue=4|pages=1657–1670|doi=10.1086/301042|bibcode=1999AJ....118.1657C|arxiv=astro-ph/9905350|hdl=11370/f890fe5e-7780-4296-b2e0-a1e6e4b51f11|s2cid=17566586}}</ref> and is approaching [[Earth]] at 234&nbsp;km/s.<ref name="Coleetal1999">{{cite journal|author1=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|date=1999|title=Stellar Populations at the Center of IC 1613|journal=The Astronomical Journal|volume=118|issue=4|pages=1657–1670|arxiv=astro-ph/9905350|bibcode=1999AJ....118.1657C|doi=10.1086/301042|author19=Trauger, John T.|author20=Watson, Alan M.|author21=Westphal, James R.|author18=Stapelfeldt, Karl R.|author17=Scowen, Paul A.|author15=Krist, John E.|author14=Hester, Jeff J.|author13=Grillmair, Carl J.|author12=Griffiths, Richard E.|author16=Meadows, Vikki|s2cid=17566586}}</ref>

There are many faint galaxies close to IC 1613, 14 of which are catalogued as members of a yet-unnamed [[galaxy cluster]] located at z≈0.20.<ref name="Krienke2001">{{cite journal |author=Karl Krienke |author2=Paul W. Hodge |date=2001 |title=Hubble Space Telescope Photometry of Clusters of Galaxies behind the Dwarf Irregular Galaxies DDO 216 and IC 1613 and the Small Magellanic Cloud |journal=[[Publications of the Astronomical Society of the Pacific]] |volume=113 |issue=787 |pages=1115–1121 |bibcode=2001PASP..113.1115K |doi=10.1086/322838}}</ref>

== Stellar population ==
It is one of the few irregular dwarf galaxies in the Local group where RR Lyrae-type variable stars have been observed. Others include the Magellanic Clouds. In 1999, Cole et al.<ref name="Coleetal1999" /> used the [[Hubble Space Telescope]] (HST) to find that the dominant [[stellar population|population]] of this galaxy has an age of ~7 Gyr.  Using its [[Hess diagram]], they found that its evolutionary history may be similar to that of the [[Pegasus Dwarf Irregular Galaxy]].  Both galaxies are classified as Ir V in the DDO system. Also in 1999, Antonello et al. found five cepheids of [[Population II]] in IC 1613, giving self-evident support for the existence of a very old stellar population component of IC 1613.  In 1999, King, Modjaz, & Li discovered the first [[nova]] ever detected in IC 1613.<ref name="Bergh2000">{{Cite journal
 | last1 = van den Bergh
 | first1 = Sidney
 | author-link1 = Sidney van den Bergh
 | title = Updated Information on the Local Group
 | date = April 2000
 | journal = The Publications of the Astronomical Society of the Pacific
 | volume = 112
 | issue = 770
 | bibcode = 2000PASP..112..529V
 | pages = 529–536
 | doi = 10.1086/316548
 |arxiv = astro-ph/0001040 | s2cid = 1805423
 }}</ref>

IC 1613 contains a [[Wolf–Rayet stars|WO star]] known as [[DR1 (star)|DR1]], which might be the only Wolf–Rayet star in the galaxy,<ref>{{Cite journal |last1=Neugent |first1=Kathryn |last2=Massey |first2=Philip |date=2019-08-01 |title=The Wolf–Rayet Content of the Galaxies of the Local Group and Beyond |journal=Galaxies |volume=7 |issue=3 |pages=74 |arxiv=1908.06238 |bibcode=2019Galax...7...74N |doi=10.3390/galaxies7030074 |doi-access=free}}</ref><ref>{{cite journal |last1=Tramper |first1=F. |last2=Straal |first2=S. M. |last3=Sanyal |first3=D. |last4=Sana |first4=H. |last5=De Koter |first5=A. |last6=Gräfener |first6=G. |last7=Langer |first7=N. |last8=Vink |first8=J. S. |last9=De Mink |first9=S. E. |author9-link=Selma de Mink |last10=Kaper |first10=L. |year=2015 |title=Massive stars on the verge of exploding: The properties of oxygen sequence Wolf–Rayet stars |journal=Astronomy & Astrophysics |volume=581 |pages=A110 |arxiv=1507.00839 |bibcode=2015A&A...581A.110T |doi=10.1051/0004-6361/201425390 |s2cid=56093231}}</ref> although a candidate WC+O binary, [[SPIRITS14bqe]], has been found.<ref>{{Cite journal |last1=Lau |first1=Ryan M. |last2=Hankins |first2=Matthew J. |last3=Kasliwal |first3=Mansi M. |last4=Bond |first4=Howard E. |last5=De |first5=Kishalay |last6=Jencson |first6=Jacob E. |last7=Moffat |first7=Anthony F. J. |last8=Smith |first8=Nathan |last9=Williams |first9=Peredur M. |date=2021-03-01 |title=Revealing Efficient Dust Formation at Low Metallicity in Extragalactic Carbon-rich Wolf–Rayet Binaries |journal=The Astrophysical Journal |volume=909 |issue=2 |pages=113 |arxiv=2011.09732 |bibcode=2021ApJ...909..113L |doi=10.3847/1538-4357/abd8cd |issn=0004-637X |s2cid=227053768 |doi-access=free}}</ref> A [[luminous blue variable]] candidate<ref>{{Cite journal |last1=Herrero |first1=A. |last2=Garcia |first2=M. |last3=Uytterhoeven |first3=K. |last4=Najarro |first4=F. |last5=Lennon |first5=D. J. |last6=Vink |first6=J. S. |last7=Castro |first7=N. |year=2010 |title=The nature of V39: an LBV candidate or LBV impostor in the very low metallicity galaxy IC 1613? |journal=Astronomy and Astrophysics |language=en |volume=513 |pages=A70 |arxiv=1003.0875 |bibcode=2010A&A...513A..70H |doi=10.1051/0004-6361/200913562 |issn=0004-6361 |s2cid=54068837}}</ref> has been proposed but a revised classification led to a B2.5 III type.<ref name=":0">{{Cite journal |last1=Garcia |first1=M. |last2=Herrero |first2=A. |year=2013 |title=The young stellar population of IC 1613 |journal=Astronomy & Astrophysics |language=en |volume=551 |pages=A74 |arxiv=1211.4582 |bibcode=2013A&A...551A..74G |doi=10.1051/0004-6361/201219977 |issn=0004-6361 |s2cid=56300058}}</ref> Moreover, a rich population of [[OB star|OB-type]]<ref name=":0" /> stars and [[Stellar association#OB associations|OB associations]]<ref>{{Cite journal |last1=Garcia |first1=M. |last2=Herrero |first2=A. |last3=Castro |first3=N. |last4=Corral |first4=L. |last5=Rosenberg |first5=A. |year=2012 |title=The young stellar population of IC 1613 |journal=Astronomy & Astrophysics |language=en |volume=523 |pages=A23 |arxiv=1211.4582 |bibcode=2010A&A...523A..23G |doi=10.1051/0004-6361/201015243 |issn=0004-6361 |s2cid=120326367}}</ref> has been discovered.

[[File:Caldwell 51 (50290991758).jpg|thumb|left|[[Hubble Space Telescope|Hubble]] image of the central part of IC 1613, showing the faint galaxies of a background galaxy cluster.]][[GHV-62024]] is a [[O-type star|O6-type star]] located in this [[galaxy]] that shows characteristics of [[F-type star|F-type stars]]. It has a fast rotation which likely causes strong [[CNO cycle|CNO]] mixing, the products of which contaminate the stars surface.<ref>{{Cite journal |last1=Herrero |first1=A. |last2=Garcia |first2=M. |last3=Puls |first3=J. |last4=Uytterhoeven |first4=K. |last5=Najarro |first5=F. |last6=Lennon |first6=D. J. |last7=Rivero-González |first7=J. G. |date=2012-07-01 |title=A peculiar Of star in the Local Group galaxy IC 1613 |url=https://www.aanda.org/articles/aa/abs/2012/07/aa18383-11/aa18383-11.html |journal=Astronomy & Astrophysics |language=en |volume=543 |pages=A85 |doi=10.1051/0004-6361/201118383 |arxiv=1206.1238 |bibcode=2012A&A...543A..85H |issn=0004-6361}}</ref>

=== Supernova remnants ===
Many studies have studied the [[interstellar medium]] of IC 1613 such as H l and H ll complexes. There has currently been one recognized [[supernova remnant]] (SNR) which has been named [[S8 (Supernova remnant)|S8]]. There may also be another remnant with a shell-like structure with a diameter of 55 parsecs.<ref>{{Cite journal |last1=Glasman |first1=Pénélope |last2=Drissen |first2=Laurent |last3=St.-Louis |first3=Nicole |date=2025-05-22 |title=Spectroscopic Evidence for a New Supernova Remnant in IC 1613 |journal=Research Notes of the AAS |volume=9 |issue=5 |pages=121 |doi=10.3847/2515-5172/addab0 |doi-access=free |bibcode=2025RNAAS...9..121G |issn=2515-5172}}</ref>{{clear}}

==References==
{{reflist}}

==External links==
*{{commonscat-inline}}
*{{WikiSky}}
{{Sky|01|04|47.8|+|02|07|04|2380000}}

{{Ugc10}}
{{Caldwell catalogue}}
{{Cetus}}

{{DEFAULTSORT:IC 1613}}
[[Category:Dwarf irregular galaxies]]
[[Category:Local Group]]
[[Category:Cetus]]
[[Category:IC objects|1613]]
[[Category:UGC objects|00668]]
[[Category:Principal Galaxies Catalogue objects|03844]]
[[Category:Caldwell objects|051b]]
[[Category:Astronomical objects discovered in 1906]]