IC 342 (also known as Caldwell 5) is an

intermediate spiral galaxy An intermediate spiral galaxy is a galaxy that is in between the classifications of a barred spiral galaxy and an unbarred spiral galaxy. It is designated as SAB in the galaxy morphological classification system devised by Gerard de Vaucouleu ...

in the constellation Camelopardalis, located relatively close to the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...

. Despite its size and actual brightness, its location behind dusty areas near the

galactic equator The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way Galaxy, and the fundamental plane parallel to an ap ...

makes it difficult to observe, leading to the nickname "The Hidden Galaxy", though it can readily be detected even with binoculars. If the galaxy were not obscured, it would be visible by naked eye. The dust makes it difficult to determine its precise distance; modern estimates range from about 7 mega

light-years A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

(Mly) to about 11 Mly. The galaxy was discovered by

William Frederick Denning William Frederick Denning (25 November 1848 – 9 June 1931) was a British amateur astronomer who achieved considerable success without formal scientific training. He is known for his catalogues of meteor radiants, observations of Jupiter's re ...

in 1892. It is one of the brightest in the

IC 342/Maffei Group The IC 342/Maffei Group (also known as the IC 342 Group or the Maffei 1 Group) corresponds to one or two galaxy groups close to the Local Group. The member galaxies are mostly concentrated around either IC 342 or Maffei 1, which would be the brig ...

, one of the closest

galaxy group A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 1010 times the luminosity of the Sun); collections of galaxie ...

s to the

Local Group The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly , and a total mass of the order of . It consists of two collections of galaxies in a "dumbbell" shape: the Milky Way and its satellites form ...

. Edwin Hubble first thought it to be in the Local Group, but it was later determined not to be a member. In 1935,

Harlow Shapley Harlow Shapley (November 2, 1885 – October 20, 1972) was an American scientist, head of the Harvard College Observatory (1921–1952), and political activist during the latter New Deal and Fair Deal. Shapley used Cepheid variable stars to estim ...

found that it was wider than the

full moon The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon (when the ecliptic longitudes of the Sun and Moon differ by 180°). This means ...

, and by angular size the third-largest spiral galaxy then known, smaller only than the

Andromeda Galaxy The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gal ...

(M31) and the

Triangulum Galaxy The Triangulum Galaxy is a spiral galaxy 2.73 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC (''New General Catalogue)'' 598. With the D25 isophotal diameter of , the Triangulum Ga ...

(M33).Border Cities Star (Windsor, Ontario)
"Spiral Galaxy Third Biggest"
24 June 1935, p.8 (Modern estimates are more conservative, giving the apparent size as one-half to two-thirds the diameter of the full moon). It has an H II nucleus. The galaxy has a diameter of 75,000 light-years. In 2020, the galaxy KKH 32 was identified as the first known satellite of IC 342 that is a

dwarf spheroidal galaxy A dwarf spheroidal galaxy (dSph) is a term in astronomy applied to small, low-luminosity galaxies with very little dust and an older stellar population. They are found in the Local Group as companions to the Milky Way and to systems that are com ...

. Unlike galaxies with large bulges such as the

, IC 342 has a relatively few dwarf satellite galaxies. KKH 32 is located about 10.2 million light-years (3.12 megaparsecs) away, and has a diameter of about 4,300 light-years (1.32 kiloparsecs). Hubble's Hidden Galaxy

References

External links

NASA Astronomy Picture of the Day
– 22 December 2010

* {{DEFAULTSORT:IC 342 18920819 IC 0342 IC 0342 IC 0342 0342 02847 13826 005b

See also

References

External links