Globular clusters are extremely dense, gravitationally bound, spherical star clusters that are associated with massive galaxies. About two hundred are known to orbit the Milky Way. Globulars range in mass from 10^5 to 10^7 times the mass of Sun. The largest globular clusters (e.g., Omega Centauri) are in fact small galaxies unto themselves, undergoing tidal stripping from their parent galaxy. Most globulars are very old, among the oldest structures in the Universe. For this reason globulars are best studied at long wavelengths, notably the near-infrared, where evolved (red giant) stars are giving off most of their light.


Globular cluster "47 Tuc" (NGC 104) as imaged in the near-infrared. The J-band (1.2 microns) is shown in Blue, the H-band (1.6 microns) in Green, and the Ks-band (2.2 microns) in Red. The field of view is ~22 arcmin. The data comes from 2MASS and the Large Galaxy Atlas (Jarrett et al.).


More famous globular clusters of the Milky Way


M2
M5
M9
M13 (Hercules)
M15

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[Last Updated: 2004 Jan 30; by Tom Jarrett]