Large group of stars less bound than globular clusters
"Galactic cluster" redirects here. Not to be confused with galaxy cluster.
Open cluster
The Pleiades is one of the most famous open clusters.
Characteristics
Type
Loose cluster of stars
Size range
< 30 ly in diameter
Density
~ 1.5 stars / cubic ly
External links
Media category
Q11387
Additional Information
An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and many more are thought to exist.[1] Each one is loosely bound by mutual gravitational attraction and becomes disrupted by close encounters with other clusters and clouds of gas as they orbit the Galactic Center. This can result in a loss of cluster members through internal close encounters and a dispersion into the main body of the galaxy.[2] Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years. In contrast, the more massive globular clusters of stars exert a stronger gravitational attraction on their members, and can survive for longer. Open clusters have been found only in spiral and irregular galaxies, in which active star formation is occurring.[3]
Young open clusters may be contained within the molecular cloud from which they formed, illuminating it to create an H II region.[4] Over time, radiation pressure from the cluster will disperse the molecular cloud. Typically, about 10% of the mass of a gas cloud will coalesce into stars before radiation pressure drives the rest of the gas away.
Open clusters are key objects in the study of stellar evolution. Because the cluster members are of similar age and chemical composition, their properties (such as distance, age, metallicity, extinction, and velocity) are more easily determined than they are for isolated stars.[1] A number of open clusters, such as the Pleiades, the Hyades and the Alpha Persei Cluster, are visible with the naked eye. Some others, such as the Double Cluster, are barely perceptible without instruments, while many more can be seen using binoculars or telescopes. The Wild Duck Cluster, M11, is an example.[5]
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An opencluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the...
45, and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the...
The Beehive Cluster (also known as Praesepe (Latin for "manger", "cot" or "crib"), M44, NGC 2632, or Cr 189), is an opencluster in the constellation Cancer...
OpenCluster Framework (OCF) is a set of standards for computer clustering. The project started as a working group of the Free Standards Group, now part...
Messier 93 or M93, also known as NGC 2447 or the Critter Cluster, is an opencluster in the modestly southern constellation Puppis, the imagined poop...
millions of old stars which are gravitationally bound. Openclusters are more loosely clustered groups of stars, generally containing fewer than a few...
This is a list of openclusters located in the Milky Way. An opencluster is an association of up to a few thousand stars that all formed from the same...
and sometimes known as the Ptolemy Cluster, is an opencluster of stars in the constellation of Scorpius. The cluster is easily detectable with the naked...
The Butterfly Cluster (cataloged as Messier 6 or M6, and as NGC 6405) is an opencluster of stars in the southern constellation of Scorpius. Its name derives...
A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards their centers...
astronomy, an opencluster family is a group of approximately coeval (age range ∼ {\displaystyle \sim } 30 Myr) young open star clusters located in a relatively...
The Wild Duck Cluster (also known as Messier 11, or NGC 6705) is an opencluster of stars in the constellation Scutum (the Shield). It was discovered by...
or NGC 2682) and sometimes called the King Cobra Cluster or the Golden Eye Cluster is an opencluster in the southern, equatorial half of Cancer. It was...
Messier 103 (also known as M103, or NGC 581) is a small opencluster of many faint stars in Cassiopeia. It was discovered on 27 March 1781 by Pierre Méchain...
is most noted for observing that the brightness of the more distant openclusters was lower than expected, and the stars appeared more red. This was explained...
is an opencluster of stars in the southern constellation of Scutum. It was discovered by Charles Messier in 1764. This 8th magnitude cluster is a challenge...
known as the Dragonfly Cluster, E.T. Cluster, Owl Cluster, Kachina Doll Cluster or Phi Cassiopeiae Cluster) is an open star cluster in the constellation...
Messier 52 or M52, also known as NGC 7654 or the Scorpion Cluster, is an opencluster of stars in the highly northern constellation of Cassiopeia. It...
Messier 34 (also known as M34, NGC 1039, or the Spiral Cluster) is a large and relatively near opencluster in Perseus. It was probably discovered by Giovanni...
and the Christmas Tree Cluster. Two other objects are within this designation but not officially included, the Snowflake Cluster, and the Fox Fur Nebula...
In astronomy, an opencluster remnant (OCR) is the final stage in the evolution of an open star cluster. Viktor Ambartsumian (1938) and Lyman Spitzer (1940)...
35 or M35, also known as NGC 2168 or the Shoe-Buckle Cluster, is a relatively close opencluster of stars in the west of Gemini, at about the declination...
(also known as M37, NGC 2099, or the Salt and Pepper Cluster) is the brightest and richest opencluster in the constellation Auriga. It was discovered by...
as IC 4725, is an opencluster of stars in the southern constellation of Sagittarius. The first recorded observation of this cluster was made by Philippe...
halo of the parent galaxy Opencluster, a spherical collection of stars that orbits a galaxy in the galactic plane Cancer cluster, in biomedicine, an occurrence...
Messier 21 or M21, also designated NGC 6531 or Webb's Cross, is an opencluster of stars located to the north-east of Sagittarius in the night sky, close...
Messier 36 or M36, also known as NGC 1960 or the Pinwheel Cluster, is an opencluster of stars in the somewhat northern Auriga constellation. It was discovered...
Global Information
Media category
Q11387