NGC 604 is an H II region inside the Triangulum Galaxy. It was discovered by William Herschel on September 11, 1784. It is among the largest H II regions in the Local Group of galaxies; at the galaxy's estimated distance of 2.7 million

light-year 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 ...

s, its longest diameter is roughly 1,520 light years (~460 parsecs), over 40 times the size of the visible portion of the

Orion Nebula The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae and is visible to the naked eye in the nig ...

. It is over 6,300 times more

luminous Luminous may refer to: * Luminous flame, a flame emitting visible light Music * Luminous (group), a South Korean boy band * ''Luminous'' (EP), an EP by Cesium 137 * ''Luminous'' (John Hicks and Elise Wood album), 1985–88 * Luminous (The Hor ...

than the

, and if it were at the same distance it would outshine Venus. Its gas is ionized by a cluster of massive

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

s at its center with 200 stars of spectral type O and WR, a mass of 10⁵

solar mass The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

es, and an age of 3.5 million years; however, unlike the

Large Magellanic Cloud The Large Magellanic Cloud (LMC), or Nubecula Major, is a satellite galaxy of the Milky Way. At a distance of around 50 kiloparsecs (≈160,000 light-years), the LMC is the second- or third-closest galaxy to the Milky Way, after the ...

's Tarantula Nebula central cluster ( R136), NGC 604's one is much less compact and more similar to a large

stellar association A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. Stellar associations will normally contain from 10 to 100 or more stars. The stars share a common origin, but have become gravitationally u ...

References

*Some data in the table was updated from Sue French's column "Deep-sky Wonders", in the January 2006 issue of Sky & Telescope, p. 83.

External links

Nebula NGC 604 @ SEDS Messier pages
* * {{DEFAULTSORT:NGC 0604 H II regions Triangulum (constellation) 0604 Triangulum Galaxy 17840911 Star-forming regions

See also

References

External links