Messier 14

Messier 14 (also known as M14 or NGC 6402) is a globular cluster of stars in the constellation Ophiuchus. It was discovered by Charles Messier in 1764.

Messier 14
Messier 14, from 2MASS
Observation data (J2000 epoch)
ClassVIII[1]
ConstellationOphiuchus
Right ascension 17h 37m 36.15s[2]
Declination–03° 14′ 45.3″[2]
Distance30.3 kly (9.3 kpc)[3]
Apparent magnitude (V)+8.32[2]
Apparent dimensions (V)11.0′
Physical characteristics
Mass1.04×106[3] M☉
Radius50 ly[4]
Metallicity = –1.28[3] dex
Other designationsNGC 6402[2]

At a distance of about 30,000 light-years, M14 contains several hundred thousand stars. At an apparent magnitude of +7.6 it can be easily observed with binoculars. Medium-sized telescopes will show some hint of the individual stars of which the brightest is of magnitude +14.

The total luminosity of M14 is in the order of 400,000 times that of the Sun corresponding to an absolute magnitude of -9.12. The shape of the cluster is decidedly elongated. M14 is about 100 light-years across.[5]

A total of 70 variable stars are known in M14, many of the W Virginis variety common in globular clusters. In 1938, a nova appeared, although this was not discovered until photographic plates from that time were studied in 1964. It is estimated that the nova reached a maximum brightness of magnitude +9.2, over five times brighter than the brightest 'normal' star in the cluster.

Slightly over 3° southwest of M14 lies the faint globular cluster NGC 6366.

  • Messier 14 with amateur telescope
  • Map showing location of Messier 14
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References
  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. "NGC 6402". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-15.
  3. Boyles, J.; et al. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal, 742 (1): 51, arXiv:1108.4402, Bibcode:2011ApJ...742...51B, doi:10.1088/0004-637X/742/1/51.
  4. distance × sin( diameter_angle / 2 ) = 50 ly radius
  5. "Messier 14 | Messier Objects". Retrieved 2020-04-14.

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