NGC 1806 is a globular cluster located within the Large Magellanic Cloud within the constellation of Dorado (the dolphin-fish), an area of the sky best seen from the Earth's southern hemisphere. It was discovered in 1836 by the British astronomer John Herschel. At an aperture of 50 arcseconds, its apparent V-band magnitude is 11.00, but at this wavelength, it has 0.05 magnitudes of interstellar extinction.[3]

NGC 1806
NGC 1806 image taken by the Hubble Space Telescope
Observation data (J2000 epoch)
ClassVI[1]
ConstellationDorado
Right ascension05h 02m 11.180s[2]
Declination−67° 59′ 05.89″[2]
Apparent magnitude (V)11.00[3]
Physical characteristics
Mass7.6×104[3] M
Estimated age1.60±0.05 Gyr[3]
Other designationsNGC 1806, KMHK 462, [SL63] 184
See also: Globular cluster, List of globular clusters

NGC 1806 is about 1.6 billion years old. Its estimated mass is 7.6×104 M, and its total luminosity is 1.42×105 L, leading to a mass-to-luminosity ratio of 0.54 M/L.[3] All else equal, older star clusters have higher mass-to-luminosity ratios; that is, they have lower luminosities for the same mass.[3]

References

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  1. ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin, 849 (849): 11–14, Bibcode:1927BHarO.849...11S
  2. ^ a b "NGC 1806". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 8 January 2019.
  3. ^ a b c d e f Song, Ying-Yi; Mateo, Mario; Bailey, John I.; Walker, Matthew G.; Roederer, Ian U.; Olszewski, Edward W.; Reiter, Megan; Kremin, Anthony (2021). "Dynamical masses and mass-to-light ratios of resolved massive star clusters – II. Results for 26 star clusters in the Magellanic Clouds". Monthly Notices of the Royal Astronomical Society. 504 (3): 4160–4191. arXiv:2104.06882. doi:10.1093/mnras/stab1065.
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