View source for NGC 7742

{{Short description|Galaxy in the constellation Pegasus}}
{{Infobox galaxy
| name = [[New General Catalogue|NGC]] 7742<ref name="AJS">{{cite journal
 | last1 = Filho | first1 = M. E.
 | last2 = Barthel | first2 = P. D.
 | last3 = Ho | first3 = L. C.
 | date=October 2002
 | title = The Nature of Composite LINER/H<sub>II</sub> Galaxies, Part II
 | journal = The Astrophysical Journal Supplement
 | volume = 142
 | issue = 2
 | pages = 223–238
 | issn = 0067-0049
 | doi = 10.1086/341786
 | arxiv = astro-ph/0205196 | bibcode = 2002ApJS..142..223F | s2cid = 16100301
 }}
</ref>
| image = [[Image:Seyfert Galaxy NGC 7742.jpg|300px]]
| caption = A [[Hubble Space Telescope]] (HST) image of NGC 7742.<br>Credit: [[NASA]]/[[ESA]]/[[STScI]]/[[Association of Universities for Research in Astronomy|AURA]].
| epoch = [[J2000]]
| constellation name = [[Pegasus (constellation)|Pegasus]]
| ra = {{RA|23|44|15.7425}}<ref name="ned">{{cite web
  | title=NASA/IPAC Extragalactic Database
  | work=Results for object NGC 7742
  | url=https://ned.ipac.caltech.edu/byname?objname=NGC+7742
  | accessdate=2006-08-20}}</ref>
| dec = {{DEC|+10|46|01.3}}<ref name="ned" />
| size_v = 1.778 × 1.698 [[Minute of arc|moa]]<ref name="SINBAD">{{cite web
  | title=Centre de Données astronomiques de Strasbourg
  | work=Results for NGC 7742
  | url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ngc7742
  | accessdate=2008-07-09}}</ref>
| appmag_v = 12.35<ref name="ned" />
| type = SA(r)b,<ref name="ned" /> [[LINER]]/[[Seyfert galaxy|HII]]<ref name="ned" />
| size = ~{{convert|15.55|kpc|ly|abbr=on|lk=on|order=flip}} (estimated){{r|ned}}
| h_radial_v = {{val|1663|1|u=km/s}}<ref name="ned" />
| z = {{val|0.005547|0.000003}}<ref name="ned" />
| gal_v = {{val|1809|6|u=km/s}}<ref name="ned" />
| dist_ly = {{convert|72.4|+/-|6.2|Mly|Mpc|2|lk=on|abbr=on}}
| names = {{odlist | PGC= 72260 | IRAS= 23417+1029 | CGCG= 432-023 | UGC= 12760 | MCG= +02-60-010 | name= UZC J234415.8+104601 | 2MASX= J23441571+1046015}}<ref name="ned" />
| references = [[SIMBAD]]: [http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC7742 Search NGC 7742 data]
}}

'''NGC 7742''' (also known as the '''Fried Egg Galaxy''') is a face-on unbarred [[spiral galaxy]]  in the [[constellation]] [[Pegasus constellation|Pegasus]]. Its velocity with respect to the [[cosmic microwave background]] is 1292 ± 26{{nbsp}}km/s, which corresponds to a [[Hubble's law|Hubble distance]] of {{convert|19.06 ± 1.39|Mpc|Mly|abbr=on|lk=on|order=flip}}.{{r|ned}} In addition, six ''non-redshift'' measurements give a farther distance of {{convert|25.783 ± 8.129|Mpc|Mly|abbr=on|lk=on|order=flip}}.<ref>{{cite web | url = https://ned.ipac.caltech.edu/cgi-bin/nDistance?name=NGC+7742 | title = Distance Results for NGC{{nbsp}}7742 | website = NASA/IPAC EXTRAGALACTIC DATABASE | publisher = [[NASA]] | access-date = 7 December 2024}}</ref> It was discovered by astronomer [[William Herschel]] on 18 Oct 1784.<ref name="selig">{{cite web | url = https://cseligman.com/text/atlas/ngc77.htm#7742 | title = New General Catalogue Objects: NGC{{nbsp}}7742| last = Seligman | first = Courtney | website = Celestial Atlas | access-date = 7 December 2024}}</ref>

NGC 7742 is unusual in that it contains a ring but no bar.<ref name="silchenkomoiseev2006">{{cite journal
  | author=O. K. Sil'chenko
  | author2=A. V. Moiseev
  | title=Nature of Nuclear Rings in Unbarred Galaxies: NGC 7742 and NGC 7217
  | journal=Astronomical Journal
  | date=2006
  | volume=131
  | issue=3
  | pages=1336–1346
  | bibcode=2006AJ....131.1336S
  | doi=10.1086/499945
|arxiv = astro-ph/0512431 | s2cid=14589261
 }}</ref>  Typically, bars are needed to produce a ring structure.  The bars' gravitational forces move gas to the ends of the bars, where it forms into the rings seen in many barred spiral galaxies.  In this galaxy, however, no bar is present, so this mechanism cannot be used to explain the formation of the ring.  O. K. Sil'chenko and A. V. Moiseev proposed the ring was formed partly as the result of a merger event in which a smaller gas-rich [[dwarf galaxy]] collided with NGC 7742.  As evidence for this, they point to the unusually bright central region, the presence of highly inclined central gas disk, and the presence of gas that is counterrotating (or rotating in the opposite direction) with respect to the stars.<ref name="silchenkomoiseev2006" /> It is also classified as a Type II [[Seyfert Galaxy]].

==Supernovae==
Two [[supernova|supernovae]] have been observed in NGC 7742:
* SN{{nbsp}}1993R ([[Type_II_supernova|type{{nbsp}}II]], mag. 17) was discovered by the [[Leuschner Observatory]] Supernova Search (LOSS) on 2 June 1993.<ref>{{cite journal | bibcode=1993IAUC.5812....1T| title=Supernova 1993R in NGC 7742| last1=Treffers| first1=R. R.| last2=Leibundgut| first2=B.| last3=Filippenko| first3=A. V.| last4=Richmond| first4=M. W.| journal=International Astronomical Union Circular| date=1993| issue=5812| page=1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}1993R | url=https://www.wis-tns.org/object/1993R | publisher = [[International_Astronomical_Union|IAU]] | access-date=7 December 2024}}</ref>
* SN{{nbsp}}2014cy (type{{nbsp}}IIP, mag. 16.2) was discovered by Ken'ichi Nishimura on 31 August 2014.<ref>{{cite journal | bibcode=2014CBET.3964....1N| title=Supernova 2014cy in NGC 7742 = PSN J23441603+1046125| last1=Nishimura| first1=K.| journal=Central Bureau Electronic Telegrams| date=2014| issue=3964| page=1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}2014cy | url=https://www.wis-tns.org/object/2014cy | publisher = [[International_Astronomical_Union|IAU]] | access-date=7 December 2024}}</ref>

==See also==
* [[NGC 7217]] – a face-on spiral galaxy with identical characteristics
* [[Sombrero Galaxy]] – a similar galaxy with a dust ring

==Gallery==
<gallery heights=180 widths=180>
File:NGC7742 - SDSS DR14.jpg|NGC 7742 (SDSS DR14)
</gallery>

==References==

{{reflist}}

==External links==
*{{commons category-inline}}
*[https://web.archive.org/web/20070117183551/http://www.spacetelescope.org/images/html/opo9828a.html NGC 7742 at ESA/Hubble]
*{{WikiSky}}

{{Sky|23|44|15.7425|+|10|46|01.3|72400000}}
{{Catalogs|UGC=12760|NGC=7742}}
{{Ngc80}}

{{DEFAULTSORT:Ngc 7742}}
[[Category:Ring galaxies]]
[[Category:Unbarred spiral galaxies]]
[[Category:Pegasus (constellation)]]
[[Category:NGC objects|7742]]
[[Category:UGC objects|12760]]
[[Category:Principal Galaxies Catalogue objects|072260]]
[[Category:Astronomical objects discovered in 1784|17841018]]
[[Category:Discoveries by William Herschel]]
[[Category:MCG objects|+02-60-010]]
[[Category:IRAS catalogue objects|23417+1029]]