| 词条 | NGC 7742 |
| 释义 |
| name = NGC 7742[1] }}{{Galaxybox image | image = | caption = A Hubble Space Telescope (HST) image of NGC 7742. | credit = NASA/ESA/STScI/AURA. }}{{Galaxybox observe | epoch = J2000 | constell = Pegasus | ra = {{RA|23|44|15.7}}[2] | dec = {{DEC|+10|46|02}}[2] | appdim_v = 1.778 × 1.698 moa[3] | appmag_v = 12.35[2] }}{{Galaxybox character | g_type = SA(r)b,[2] LINER/HII[2] }}{{Galaxybox astrometry | h_radial_v = 1663 | hrv_err = 1[2] | z = 0.005547 | z_err = 0.000003[2] | gal_v = 1809 | gv_err = 6[2] | g_dist = 72.4 | dist_err = 6.2 }}{{Galaxybox catalog | names = UGC 12760,[2] MCG +02-60-010,[2] UZC J234415.8+104601,[2] 2MASX J23441571+1046015[2] }}{{Galaxybox reference | Simbad = NGC7742 Search NGC 7742 }}{{Galaxybox end}} NGC 7742 also known as Fried Egg Galaxy is a face-on unbarred spiral galaxy in the constellation Pegasus. The galaxy is unusual in that it contains a ring but no bar.[4] 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 that 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.[4] Two Type II supernovae, SN 1993R and SN 2014cy, have been detected in NGC 7742.[5] See also
References1. ^{{cite journal | last = Filho | first = M. E. | last2 = Barthel | first2 = P. D. | last3 = Ho | first3 = L. C. | date=October 2002 | title = The Nature of Composite LINER/HII 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 }} 2. ^1 2 3 4 5 6 7 8 9 10 11 {{cite web | title=NASA/IPAC Extragalactic Database | work=Results for NGC 7742 | url=http://nedwww.ipac.caltech.edu/ | accessdate=2006-08-20}} 3. ^{{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}} 4. ^1 {{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 }} 5. ^{{cite web|title=List of Supernovae|url=http://www.cbat.eps.harvard.edu/lists/Supernovae.html|publisher=IAU Central Bureau for Astronomical Telegrams|accessdate=13 September 2015}} External links
6 : Ring galaxies|Unbarred spiral galaxies|Pegasus (constellation)|NGC objects|UGC objects|Principal Galaxies Catalogue objects |
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