NGC 604

NGC 604
Emission nebula
H II region

NGC 604 inside the Triangulum Galaxy
(viewed by the Hubble Space Telescope).
Observation data: J2000 epoch
Right ascension 01h 34m 33.2s[1]
Declination +30° 47′ 06″[1]
Distance 2,700,000 ly   (840,000[2] pc)
Apparent magnitude (V) +14.0 [1]
Apparent dimensions (V) 1′.93 x 1′.2 arcmins[1]
Constellation Triangulum
Physical characteristics
Radius 760[3] ly
Absolute magnitude (V) -13.8
Notable features massive H II region

NGC 604 is an H II region inside the Triangulum Galaxy. It was discovered by William Herschel on September 11, 1784. It is one of the largest H II regions in the Local Group of galaxies; at the galaxy's estimated distance of 2.7 million light-years its longest diameter is roughly 1500 light years (460 parsecs), over 40 times the size of the visible portion of the Orion Nebula. It is over 6300 times more luminous than the Orion Nebula, and if it were at the same distance it would outshine Venus. Like all emission nebulae, its gas is ionized by a cluster of massive stars at its center.[4] with 200 stars of spectral type O and WR, a mass of 105 solar masses, and an age of 3.5 million years;[2] however, unlike the Large Magellanic Cloud's Tarantula Nebula central cluster (R136), NGC 604's one is much less compact and more similar to a large stellar association, being considered the prototypical example of a Scaled OB Association (SOBA)[5]

NASA/ESA Hubble Space Telescope provides the sharpest view of NGC 604 so far obtained.

References

  1. 1 2 3 4 "NASA/IPAC Extragalactic Database". Results for NGC 604. Retrieved 2006-09-03.
  2. 1 2 Barba, Rodolfo (2004). "An in-depth analysis of a prototypical giant H II region: NGC 604". HST Proposal ID #10419. Bibcode:2004hst..prop.6732B.
  3. ↑ distance × sin( diameter_angle / 2 ) = 760 ly. radius
  4. ↑ Nemiroff, R.; Bonnell, J., eds. (2 November 2002). "NGC 604: Giant Stellar Nursery". Astronomy Picture of the Day. NASA.
  5. ↑ Maíz-Apellániz, J.; Pérez, E.; Mas-Hesse, J. M. (2004). "NGC 604, the Scaled OB Association (SOBA) Prototype. I. Spatial Distribution of the Different Gas Phases and Attenuation by Dust". The Astronomical Journal. 128 (3): 1196–1218. arXiv:astro-ph/0406130Freely accessible. Bibcode:2004AJ....128.1196M. doi:10.1086/422925.
  • 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.
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