NGC 2232 is a bright open star cluster in the equatorial constellation of Monoceros, centered on the star 10 Monocerotis.[3] It is located in the Gould Belt close to the Orion Nebula cluster,[6] at a mean distance of 1,060 ly from the Sun.[2] The average radial velocity of the cluster members is 26.6±0.77 km/s.[7] This is one of the nearest open clusters to the Sun, which makes it a potentially useful target for studying young stars and their transition to the main sequence.[8]

NGC 2232
NGC 2232.png
NGC 2232 (taken from Stellarium)
Observation data (J2000 epoch)
Right ascension06h 27m 15s[1]
Declination–04° 45′ 30″[1]
Distance1,060 ly (325 pc)[2]
Apparent magnitude (V)3.9[3]
Apparent dimensions (V)30′ [3]
Physical characteristics
Mass< 100[4] M
Radius~15 ly[4]
Estimated age30.9 Myr[2]
Other designationsCr 93, C 0624-047[5]
See also: Open cluster, List of open clusters
Map showing the location of NGC 2232

The cluster has an angular radius of 36 and a core angular radius of 7.2′. It is a sparse cluster with twenty high–probability members.[2] This is considered a super-solar cluster, with the components generally having a higher abundance of iron compared to the Sun. The mean metallicity is 0.22±0.09 or 0.32±0.08, depending on what assumptions are made.[7] At least four cluster members display an infrared excess at a wavelength of 8μm that is suggestive of warm dust, while the A-type star HD 45435 displays a strong excess at 24μm. The latter may indicate the star is in an early evolutionary state.[6] Only one member of the cluster appears to be chemically peculiar.[9]


  1. ^ a b Wu, Zhen-Yu; et al. (November 2009), "The orbits of open clusters in the Galaxy", Monthly Notices of the Royal Astronomical Society, 399 (4): 2146–2164, arXiv:0909.3737, Bibcode:2009MNRAS.399.2146W, doi:10.1111/j.1365-2966.2009.15416.x, S2CID 6066790.
  2. ^ a b c d Kharchenko, N. V.; et al. (2005), "Astrophysical parameters of Galactic open clusters", Astronomy and Astrophysics, 438 (3): 1163–1173, arXiv:astro-ph/0501674, Bibcode:2005A&A...438.1163K, doi:10.1051/0004-6361:20042523, S2CID 9079873.
  3. ^ a b c Dunlop, Storm (2005). Atlas of the Night Sky. Collins. ISBN 978-0-00-717223-8.
  4. ^ a b Finlay, Warren H. (2014), Concise Catalog of Deep-sky Objects, The Patrick Moore Practical Astronomy Series (2nd ed.), Springer Science & Business Media, p. 188, ISBN 978-3-319-03169-9.
  5. ^ "NGC 2232". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-04-12.
  6. ^ a b Currie, Thayne; et al. (November 2008), "A Spitzer Study of Debris Disks in the Young Nearby Cluster NGC 2232: Icy Planets Are Common around ~1.5-3 M☉ Stars", The Astrophysical Journal, 688 (1): 597–615, arXiv:0807.2056, Bibcode:2008ApJ...688..597C, doi:10.1086/591842, S2CID 28733060.
  7. ^ a b Monroe, TalaWanda R.; Pilachowski, Catherine A. (December 2010), "Metallicities of Young Open Clusters. I. NGC 7160 and NGC 2232", The Astronomical Journal, 140 (6): 2109–2123, arXiv:1010.0739, Bibcode:2010AJ....140.2109M, doi:10.1088/0004-6256/140/6/2109, S2CID 119241382.
  8. ^ Orban, Chris; Patten, Brian (January 1, 2004), Late-Type Membership of the Open Cluster NGC 2232, Greenbelt, MD, United States: NASA Goddard Space Flight Center, retrieved 2020-04-13.
  9. ^ Jenkner, H.; Maitzen, H. M. (November 1987), "Photoelectric search for CP2-stars in open clusters. X. NGC 2232, NGC2343, CR 140, and TR 10.", Astronomy and Astrophysics, Supplemental Series, 71: 255–261, Bibcode:1987A&AS...71..255J.

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