Article · Wikipedia archive · Last revised Jul 8, 2026

NGC 604

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-years, its longest diameter is roughly 1,520 light years (~460 parsecs), over 40 times the size of the visible portion of the Orion Nebula. It is over 6,300 times more luminous than the Orion Nebula, and if it were at the same distance it would outshine Venus. Its gas is ionized by a cluster of massive stars at its center with 200 stars of spectral type O and WR, a mass of 105 solar masses, and an age of 3.5 million years; 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.

Last revised
Jul 8, 2026
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≈ 2 min
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Citations
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Wikipedia ↗
NGC 604
Emission nebula
H II region
NGC 604 inside the Triangulum Galaxy
(viewed by the James Webb Space Telescope)
Observation data: J2000 epoch
Right ascension01h 34m 33.2s1
Declination+30° 47′ 06″1
Distance2,700,000 ly   (840,0002 pc)
Apparent magnitude (V)+14.01
Apparent dimensions (V)1.93′ x 1.2′ arcmins1
ConstellationTriangulum
Physical characteristics
Radius7603 ly
Absolute magnitude (V)-13.8
Notable featuresmassive H II region
3.5 million years old2

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-years, its longest diameter is roughly 1,520 light years (~460 parsecs), over 40 times the size of the visible portion of the Orion Nebula. It is over 6,300 times more luminous than the Orion Nebula, and if it were at the same distance it would outshine Venus. Its gas is ionized by a cluster of massive stars at its center4 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.5

NGC 604, shown using the Hubble Space Telescope and Chandra, shows the nebula in the visible light and X-Rays source ↗
See also

See also

Notes

Notes

  • 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.
References

References

  1. "NASA/IPAC Extragalactic Database". Results for NGC 604. Retrieved 2006-09-03.
  2. Barba, Rodolfo (2004). "An in-depth analysis of a prototypical giant H II region: NGC 604". HST Proposal ID #10419: 10419. Bibcode:2004hst..prop10419B.
  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/0406130. Bibcode:2004AJ....128.1196M. doi:10.1086/422925. S2CID 8099926.
External links