A loose grouping of relativly young star grvitationally bound together. Most stars in open clusters formed as a group inside large nebulae.
Gravitationally bound concentrations of stars believed to originate from large cosmic gas and dust clouds. Smaller than a globular cluster and usually have a short lifespan as a cluster. Also see "star cluster" and "globular cluster". Ex. M45 - the Pleiades star cluster.
A group of stars that were born at the same time from a molecular cloud, and are still near to each other. They are also called galactic clusters since they exist within the galaxy's disk.
A galactic cluster, an asymmetric type of star cluster.
A shapeless, loosely packed cluster of stars.
Somewhat loose assemblage of stars, numbering dozens to hundreds, with various degrees of central condensation. In our Galaxy it is also known as a galactic cluster.
moderately loose star cluster of several hundred to several thousand stars distributed in a region a few hundred light years across. Most open star clusters are moderately young with ages approximated by their main sequence stars of earliest spectral class. ( O5 = 2; B0 = 8; B5 = 70; A0 = 400; A5 = 1,000; F0 = 3,000; F5 = 10,000 million years.) Alternate name: galactic cluster (no longer in common use). Several classification schemes exist: Shapley: (very loose and irregular); (loose and poor); (intermediately rich); (fairly rich); (considerably rich and concentrated). Another more complex scheme with three parts is due to Trumpler (1930): Concentration: (Detached; strong concentration toward center); II (Detached; weak concentration toward center); III (Detached; no concentration toward center); IV (Not well detached from surrounding star field). Range in Brightness: (Small range in brightness); (Moderate range in brightness); (Large range in brightness). Richness: (Poor: Less than 50 stars); (Moderately rich: 50 to 100 stars); (Rich: More than 100 stars). An following the Trumpler class indicates there is nebulosity associated with the cluster.
a group of star formed from a molecular cloud , the illuminated parts of which we see as one or more nebulae
a loose gravitationally bound collection of a few stars within the plane of the galaxy
a loose grouping of stars that is held together by their mutual gravity
An open cluster is a group of stars that are thought to have formed from a common cloud of dust and gas. Open clusters are also known as galactic clusters as they are generally located along the disk of spiral galaxies where star formation is more common. Open clusters have a few dozen up to a few thousand stars in a vloume up to 20 parsecs or so wide. They contain Population I stars, young and high in metallicity. Open clisters are not gravitationally bound so cluster members disperse into the general disk population of stars. Examples include the Pleiades, Hyades, both in Taurus and the Jewel Box in Crux.
A irregular, loose cluster of stars of common origin; found in the spiral arms of the Galaxy
A diffuse association of a few dozen to a few thousand stars, all of which were created together and which travel through space together. The Pleiades in Taurus and the Beehive in Cancer are familiar examples.
a loose galactic cluster of predominately young stars (e.g. Pleides M45).
A type of star cluster containing several hundred to several thousand stars distributed in a region a few light years across.
A group of young stars, possibly bound together by gravity, that formed together
a system containing a few dozen to a few thousand stars that formed from the same stellar nursery.
A collection of young stars that formed together. They may or may not be still bound by gravity. Some of the youngest open clusters are still embedded in the gas and dust from which they formed.
A comparatively loose or "open" cluster of stars, containing from a few dozen to a few thousand members, located in the spiral arms or disk of the Galaxy; sometimes referred to as a galactic cluster.
A group of stars, usually of the same age, that are bound together gravitationally.
An open cluster is a loose collection of up to about 1,000 relatively young stars that formed around the same time. An open cluster is about 10 parsecs across. Examples include the Pleiades and Hyades.
a loose cluster of a small number of stars; aka galactic cluster
A loose cluster of roughly a few hundred young stars.
Also known as a galactic cluster, an open cluster consists of numerous young stars that formed at the same time within a large cloud of interstellar dust and gas. Open clusters are located in the spiral arms or the disks of galaxies. The Pleiades is an example of an open cluster.
Open clusters are internal to our Galaxy. One particularly well known open cluster is the Pleiades (also known as the seven sisters) in the constellation of Taurus. It is said that some observers with exceptionally good eyesight can se up to 11 members of the cluster. Others were observed by Charles Messier, who catalogued objects whilst searching for comets. These are given "M" numbers e.g. M36. The ones that were not catalogued by Messier appear in other catalogues of deep sky objects such as the NGC (New General Catalogue). To the naked eye, under dark skies, the brighter open clusters appear as faint fuzzy patches but in binoculars or telescopes, their starry nature can be seen.
An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud, and are still loosely gravitationally bound to each other. In contrast, globular clusters are very tightly bound by gravity. Open clusters are found only in spiral and irregular galaxies, in which active star formation is occurring.