Globular Cluster

A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is derived from the Latin globulus—a small sphere. A globular cluster is sometimes known more simply as a globular.

Globular clusters, which are found in the halo of a galaxy, contain considerably more stars and are much older than the less dense galactic, or open clusters, which are found in the disk. Globular clusters are fairly common; there are about 150 to 158 currently known globular clusters in the Milky Way, with perhaps 10 to 20 more still undiscovered. Large galaxies can have more: Andromeda, for instance, may have as many as 500. Some giant elliptical galaxies, particularly those at the centers of galaxy clusters, such as M87, have as many as 13,000 globular clusters. These globular clusters orbit the galaxy out to large radii, 40 kiloparsecs (approximately 131,000 light-years) or more.

Every galaxy of sufficient mass in the Local Group has an associated group of globular clusters, and almost every large galaxy surveyed has been found to possess a system of globular clusters. The Sagittarius Dwarf and Canis Major Dwarf galaxies appear to be in the process of donating their associated globular clusters (such as Palomar 12) to the Milky Way. This demonstrates how many of this galaxy's globular clusters might have been acquired in the past.

Although it appears that globular clusters contain some of the first stars to be produced in the galaxy, their origins and their role in galactic evolution are still unclear. It does appear clear that globular clusters are significantly different from dwarf elliptical galaxies and were formed as part of the star formation of the parent galaxy rather than as a separate galaxy. However, recent conjectures by astronomers suggest that globular clusters and dwarf spheroidals may not be clearly separate and distinct types of objects.

Read more about Globular ClusterObservation History, Formation, Composition, Color-magnitude Diagram, Morphology, Tidal Encounters, Planets

Other articles related to "globular cluster, globular clusters, cluster":

Segue 1
... Segue 1 is a dwarf spheroidal galaxy or globular cluster situated in the Leo constellation and discovered in 2006 by Sloan Digital Sky Survey ... which is much smaller than the luminosity of a typical globular cluster ... It may once have been a globular cluster of the Sagittarius Dwarf Elliptical Galaxy, which was latter stripped from it by the tidal forces acting from the Milky Way ...
Globular Cluster - Planets
... results of a search for giant planets in the globular cluster 47 Tucanae were announced ... The very low abundance of these elements in globular clusters means that the members stars have a far lower likelihood of hosting Earth-mass planets, when compared to stars ... Hence the halo region of the Milky Way galaxy, including globular cluster members, are unlikely to host habitable terrestrial planets ...
Hydra (constellation) - Notable Features - Deep-sky Objects
... Galaxy, is located on the border of Hydra and Centaurus, M68 is a globular cluster near M83, and M48 is an open star cluster in the western end of the serpent ... M48 (NGC 2548) is an open cluster that is visible to the naked eye under dark skies ... Its shape has been described as "triangular" this 80-star cluster is unusually large, more than half a degree in diameter, larger than the diameter of the full Moon ...
List Of NGC Objects (6001–7000) - 6301-6400
... Planetary nebula Scorpius 17h 13m 44.2s -37° 06′ 16″ 7.1 6304 ESO454-SC2 Globular Cluster Ophiuchus 17h 14m 32.5s -29° 27′ 44″ 8.22 6333 Messier 9 ...
Coma Berenices - Notable Features - Star Clusters - Globular Clusters
... M53 (NGC 5024) is a globular cluster that was discovered by Johann Elert Bode in 1775 and independently by Charles Messier in February 1777 ... M53 is a Shapley class V cluster, indicating that it has intermediate concentration towards its center ... Only 1° away is NGC 5053, a globular cluster that is sparser and has a less dense nucleus of stars ...

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