Clusters, Clusters Everywhere
With it's strange sounding Arabic name, Sadr is one of the brightest, easiest stars to find at this time of year. Shining at magnitude 2.3, it is about as bright as a typical approach of the planet Saturn.
STAR CLUSTERS
Open clusters are found in the disk of the Galaxy, and therefore lie largely in the plane of the Milky Way.
Clusters of Galaxies
The Perseus Galactic Cluster
A galaxy is a huge group of stars, dust, gas, and other celestial bodies bound together by gravitational forces.
Open clusters are also sometimes called galactic clusters because they lie relatively close to us, and they are within the disk of the galaxy. Open clusters can contain anywhere from a few dozen to a few hundred stars.
Note: Further articles about clusters can be requested on the list of unwritten cluster articles.
Pages in category "Clusters"
The following 33 pages are in this category, out of 33 total.
Star Clusters
A grouping of the same types of astronomical objects. For example, stars in the Milky Way can group together into open clusters or globular clusters.
Star Clusters
A star cluster is a group of stars that share a common origin and are gravitationally bound for some length of time. They are are particularly useful to astronomers as they provide a way to study and model stellar evolution and ages.
Open clusters - NGC objects 4755, 265, 290 & 6231
Why Open Clusters are Important ...
Hybrid clusters shake up stellar evolution theories
DR EMILY BALDWIN
ASTRONOMY NOW
Posted: 02 June 2011 ...
Clusters are larger than groups, although there is no sharp dividing line between a group and a cluster. When observed visually, clusters appear to be collections of galaxies held together by mutual gravitational attraction.
Clusters are made up of two basic types of matter: luminous matter (like stars and hot gas) and dark matter. Dark matter does not shine on its own, and the only way we know it exists is because of its gravitational affect on luminous matter.
Clusters have a wide range of richness, size, and internal structure in the distribution of galaxies. It is hard to draw a line between groups and clusters. We are located in a rather distinct subgroup on the outskirts of the Virgo Cluster, viz.
Clusters of galaxies are the most recent and most massive objects to have arisen in the hierarchical structure formation of the Universe and the study of clusters tells one about the way galaxies form and evolve.
Abell clusters are large clusters of galaxies, catalogued by George O. Abell for his PhD dissertation in 1958.
Globular clusters are found both in spiral galaxies and elliptical galaxies. The Milky Way, for example, has over one hundred globular clusters throughout it's halo.
A Matter of Scale ...
1918 - Harlow Shapley demonstrates that globular clusters are arranged in an spheroid or halo whose center is not the Earth, decides, correctly, that its center is the center of the galaxy, ...
Beyond the New General Catalog there are dozens of other catalogues of deep sky objects - the Dolidze Dzimselejsvili (DoDz) open clusters catalogue is one of them.
Clusters of Galaxies
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Clusters of galaxies
There are many clusters of galaxies. Members of some of the closest can be seen with a small telescope in the constellations Virgo and Coma Berenices.
CLUSTERS OF CLUSTERS
Does the universe have even greater groupings of matter, or do galaxy clusters top the cosmic hierarchy?
rich clusters
large galaxy clusters with unusually high population densities
rich-field telescope ...
Rich Clusters
Clusters with a particularly large number of galaxies.
Richardson-Lucy Method ...
Galaxy Clusters
Most galaxies are found in groups or clusters which contain a few to thousands of galaxies bound together by their mutual gravity.
Stellar Clusters
Stellar cluster or cluster of stars is a group of stars bounded by their mutual gravity. When compared with the multiple star systems, they consist of many more stars, from tens to millions.
Galaxy Clusters
Once people realized galaxies are objects outside of our own galaxy, they noticed that galaxies are not randomly scattered across the Universe. They tend to be found in groups or clusters - what an original name! ...
clusters of galaxies Galaxies can swarm together to form groups and clusters of galaxies held together by their mutual galaxy. X-ray observations show that these enormous systems of galaxies are filled with colossal clouds of hot gas.
Clusters
A group or stars, or galaxies which are held together by their common gravity.
Color index ...
Clusters of galaxies are formed by the merger of smaller units of matter, such as galaxy groups or individual galaxies.
The clusters are both considered babies, 869 only being about 6.5 million years old, and 884 about 11-12 million years old.
Open clusters: NGC 2516, NGC 3114, NGC 3293, NGC 3532, IC 2602, I 2714, Mel 105
Globular cluster NGC 2808
Planetary nebula NGC 2867
Diffuse nebula NGC 3372 (Eta Carinae Nebula)
Variable stars eta Car ...
Star Clusters : groups of the same age
Globular clusters : old, halo, metal poor
Open clusters : young, disk, metal rich
Cluster H-R diagrams : isochrones (same age)
Young cluster isochrones
Main Sequence Turn Off point (MSTO) ...
Open clusters:NGC6709, NGC6755, NGC6749.
Globular cluster NGC6760 which has a 9.1 magnitude.
Planetary nebulae: NGC6778, NGC6741, NGC6772 ...
[8.3] CLUSTERS OF GALAXIES / COLLIDING GALAXIES
[8.4] QUASARS
[9.0] Cosmology & The Big Bang ...
Galaxy clusters are permeated by hot, X-ray emitting gas known as the intra-cluster medium.
Because clusters are all about the same actual size, we can determine their distances from their apparent sizes. This gives us another handle on how distant the stars are.
Activity 6. Apparent size as a measure of distance ...
Certain clusters contain a remarkable number of short-period variables. Thus the cluster Messier 5 was found at Harvard to contain 185 variables out of 900 stars examined. Solon I.
Globular clusters were originally defined as rich, compact, nearly spherical, groups of hundreds of thousands (or even millions) of stars.
Globular clusters: Groups of thousands to millions of old stars held together in orbits about their own center of mass and arranged in almost symmetrical (spherical) clusters.
A cluster of clusters of galaxies.
supergiant - (n.)
A post-main-sequence phase of evolution of stars of more than about 4 solar masses. Supergiants fall in the extreme upper right of the H-R diagram.
Earthquake clusters
Most earthquakes form part of a sequence, related to each other in terms of location and time.
Most globular clusters, in both the Milky Way and other galaxies, contain primarily old stars. Metallicities range from extremely metal-poor (< 1/100th of the solar value) to values close to the Sun’s.
Ages for star clusters can be estimated by comparing the H-R diagram for the cluster with theoretical models of stellar evolution, and using this technique, ages for the Pleiades of between 75 and 150 million years have been estimated.
Black Holes Goddard Space Flight Center Laboratory for High Energy Astrophysics
Star Clusters National Geographic
Constellations in the Night Sky National Geographic
Space agencies: ...
Both binoculars and Dobby at 24x showed its round glow. Next I zoomed my 10x50 field glasses back to Scorpio and caught M6 and M7 open clusters high above Southern horizon at 3:00am. Even at that power they were fully resolved. ...
The "horizontal branch" is like the main sequence: a distribution of stars on the HR diagram. The main sequence is composed of those stars burning hydrogen in equilibrium whereas the horizontal branch stars are the helium burners.
Star Clusters ...
NEBULAE & STAR CLUSTERS
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
entire Web this site ...
metal clusters (NASA Thesaurus) Bonded aggregations of like metal atoms. metal foams (NASA Thesaurus) Foamed materials formed under low gravity conditions in space from sputtered metal deposits.
The collection of clusters consisting of the , and Coma and Virgo clusters.
Unobserved mass in clusters of galaxies believed to provide sufficient gravity to bind the cluster together.
Model
An intellectual concept of how nature works ...
The oldest globular clusters contain only stars less massive than 0.7 solar masses. These low-mass stars are much dimmer than our Sun. This observation suggests that the oldest globular clusters are between 11 and 18 billion years old.
See cosmology; star clusters.
Bibliography
See I. S. Shklovsky, Stars: Their Birth, Life, and Death (1978); D. A. Cooke, The Life and Death of Stars (1985); A. Harpaz, Stellar Evolution (1994); I.
Charles Messier was a French Astronomer whose work on the discovery of comets led to the compilation of the Messier Catalogue of nebulae and star clusters. The reason Messier compiled this catalogue was to save time while comet hunting.
It is important to make this distinction because later we shall consider groupings that are physical groupings, such as star clusters and binary star systems.
The Constellations of the Zodiac ...
Most of the stars in the central bulge and in the globular clusters of the galactic halo are old, low metals stars, and halo stars account for only 0.1 to 0.2 percent of the stars near Sol.
Most galaxies form gravitationally-bound groups and clusters, with the remaining galaxies spread out in the field. Our ability to see the most distant galaxies is limited by their motion away from us.
When observing large objects such as nebulae or star clusters, a wide field of view is needed. Special wide field eyepieces are also available. These eyepieces can provide a nice, bright image full of details on large objects.
Except for the smallest members of some crater clusters, no craters smaller than 3 kilometers (1.9 miles) in diameter have been observed [Phillips et al., 1991]. The image "Crater Cluster" shows an irregular crater of approximately 14 kilometer (8.
Despite its masculine connotations, the constellation is rich in female icons; both the Hyades and Pleiades star clusters are daughters of Atlas and both are important astronomically.
Numerous candidates for the dark matter component in the halos of galaxies and clusters of galaxies have been proposed over the years, but no successful detection of any of them has yet occurred.
The Large Magellanic Cloud contains roughly 400 planetary nebulae, 700 open star clusters, 60 globular clusters and hundreds of thousands of giants and supergiants.
 See also: Cluster, Light, Star, Galaxies, Galaxy
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