NGC 7742

NGC 7742 (also known as the Fried Egg Galaxy) is a face-on unbarred spiral galaxy in the constellation Pegasus. Its velocity with respect to the cosmic microwave background is 1292 ± 26Template:Nbspkm/s, which corresponds to a Hubble distance of Template:Convert.Template:R In addition, six non-redshift measurements give a farther distance of Template:Convert.<ref>Template:Cite web</ref> It was discovered by astronomer William Herschel on 18 Oct 1784.<ref name="selig">Template:Cite web</ref>

NGC 7742 is unusual in that it contains a ring but no bar.<ref name="silchenkomoiseev2006">Template:Cite journal</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 supernovae have been observed in NGC 7742:

• SNTemplate:Nbsp1993R ([[Type_II_supernova|typeTemplate:NbspII]], mag. 17) was discovered by the Leuschner Observatory Supernova Search (LOSS) on 2 June 1993.<ref>Template:Cite journal</ref><ref>Template:Cite web</ref>
• SNTemplate:Nbsp2014cy (typeTemplate:NbspIIP, mag. 16.2) was discovered by Ken'ichi Nishimura on 31 August 2014.<ref>Template:Cite journal</ref><ref>Template:Cite web</ref>

See also

• NGC 7217 – a face-on spiral galaxy with identical characteristics
• Sombrero Galaxy – a similar galaxy with a dust ring

Gallery

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  NGC 7742 (SDSS DR14)

External links

• Template:Commons category-inline
• NGC 7742 at ESA/Hubble
• Template:WikiSky