Messier 32

Messier 32
Dwarf Satellite Galaxy Messier 32
Observation data (J2000 epoch)
ConstellationAndromeda
Right ascension00h 42m 41.8s[1]
Declination+40° 51′ 55″[1]
Redshift−200 ± 6 km/s[1]
Distance2.49 ± 0.08 Mly (763 ± 24 kpc)[2][3][4][a]
Apparent magnitude (V)8.08[5][6]
Characteristics
TypecE2[1]
Apparent size (V)8′.7 × 6′.5[1]
Notable featuresSatellite galaxy of the
Andromeda Galaxy
Other designations
M 32, NGC 221,[1] UGC 452,[1] PGC 2555,[1] Arp 168,[1] LEDA 2555

Messier 32 (also known as M32 and NGC 221) is a dwarf "early-type" galaxy about 2,650,000 light-years (810,000 pc) from the Solar System, appearing in the constellation Andromeda. M32 is a satellite galaxy of the Andromeda Galaxy (M31) and was discovered by Guillaume Le Gentil in 1749.

The galaxy is a prototype of the relatively rare compact elliptical (cE) class. Half the stars concentrate within an effective radius (inner core) of 330 light-years (100 pc).[7][8] Densities in the central stellar cusp increase steeply, exceeding 3×107 (that is, 30 million) M☉ pc−3 (that is, per parsec cubed) at the smallest sub-radii resolved by HST,[9] and the half-light radius of this central star cluster is around 6 parsecs (20 ly).[10] Like more ordinary elliptical galaxies, M32 contains mostly older faint red and yellow stars with practically no dust or gas and consequently no current star formation.[11] It does, however, show hints of star formation in the relatively recent past.[12]

  1. ^ a b c d e f g h i "NASA/IPAC Extragalactic Database". Results for NGC 221. Retrieved 2006-11-29.
  2. ^ Cite error: The named reference jensenetal2003 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference karachentsevetal2004 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Karachentsevetal2006 was invoked but never defined (see the help page).
  5. ^ "M32". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2009-11-29.
  6. ^ Armando, Gil de Paz; Boissier; Madore; Seibert; Boselli; et al. (2007). "The GALEX Ultraviolet Atlas of Nearby Galaxies". Astrophysical Journal Supplement. 173 (2): 185–255. arXiv:astro-ph/0606440. Bibcode:2007ApJS..173..185G. doi:10.1086/516636. S2CID 119085482.
  7. ^ Kent, S. M. (1987). "Surface photometry of six local group galaxies". Astronomical Journal. 94: 306–314. Bibcode:1987AJ.....94..306K. doi:10.1086/114472.
  8. ^ Mateo, M. L. (1998). "Dwarf Galaxies of the Local Group". Annual Review of Astronomy and Astrophysics. 36: 435–506. arXiv:astro-ph/9810070. Bibcode:1998ARA&A..36..435M. doi:10.1146/annurev.astro.36.1.435. S2CID 119333888.
  9. ^ Lauer, T. R.; Faber, S. M.; Currie, D. G.; Ewald, S. P.; Groth, E. J.; Hester, J. J.; Holtzman, J. A.; Light, R. M.; O'Neil Jr, E. J.; Shaya, E. J.; Westphal, J. A. (1992). "Planetary camera observations of the central parsec of M32" (PDF). Astronomical Journal. 104: 552–562. Bibcode:1992AJ....104..552L. doi:10.1086/116254.
  10. ^ Graham, A.W. and Spitler, L.R., Quantifying the coexistence of massive black holes and dense nuclear star clusters.
  11. ^ Kepple, George Robert; Sanner, Glen W. (1998). The Night Sky Observer's Guide. Vol. 1. Willmann-Bell. p. 17. ISBN 978-0-943396-58-3.
  12. ^ Rudenko, Pavlo; Worthey, Guy; Mateo, Mario (2009). "Intermediate age clusters in the field containing M31 and M32 stars". The Astronomical Journal. 138 (6): 1985–1989. Bibcode:2009AJ....138.1985R. doi:10.1088/0004-6256/138/6/1985.