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Topic: Open cluster

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In the News (Wed 17 Jul 19)

  Open cluster - Wikipedia, the free encyclopedia
Astronomers dubbed the former globular clusters, and the latter open clusters.
Open clusters are not seen in elliptical galaxies: star formation ceased many millions of years ago in ellipticals, and so the open clusters which were originally present have long since dispersed.
Because the stars in an open cluster are all at roughly the same distance from Earth, and were born at roughly the same time from the same raw material, the differences in apparent brightness among cluster members is due only to their mass.
en.wikipedia.org /wiki/Open_cluster   (3198 words)

 NationMaster.com - Encyclopedia: Open Cluster
Open clusters are found only in spiral and irregular galaxies, in which active star formation is occurring.
While most clusters become dispersed before a large proportion of their members have reached the white dwarf stage, the number of white dwarfs in open clusters is still generally much lower than would be expected, given the age of the cluster and the expected initial mass distribution of the stars.
Open clusters are preferentially found in the plane of the galaxy (thus they are also called galactic clusters); in contrast, the globular clusters are concentrated in the halo of the galaxy and can be very far out of the plane.
www.nationmaster.com /encyclopedia/Open-Cluster   (766 words)

 Open Cluster Club Introduction
Open clusters are of tremendous importance to the science of astronomy, if not to astrophysics and cosmology generally.
Whether a cluster like the Pleiades seen with delicate beauty with the unaided eye or in a small telescope or binoculars, or a cluster like NGC 7789 whose thousands of stars are seen with overpowering wonder in a large telescope, open clusters can only bring awe and amazement to the viewer.
Since open clusters are made of stars, a drawing of small dots in a pattern of the cluster is all that is needed.
www.astroleague.org /al/obsclubs/opencluster/opencluster1.html   (758 words)

 Open cluster
An open cluster is a group of stars that were born at the same time from a molecular cloud, and are still near to each other.
All the stars in an open cluster have more or less the same age and the same chemical composition, so any difference between them is solely due to their mass.
Most open clusters are dominated by their O-type and B-type giant blue stars, which are very luminous but short-lived.
www.fact-index.com /o/op/open_cluster.html   (528 words)

 Open Star Clusters
Open clusters are physically related groups of stars held together by mutual gravitational attraction.
Over 1100 open clusters are known in our Milky Way Galaxy, and this is probably only a small percentage of the total population which is probably some factor higher; estimates of as many as about 100,000 Milky Way open clusters have been given.
The first open clusters have been known since prehistoric times: The Pleiades (M45), the Hyades and the Beehive or Praesepe (M44) are the most prominent examples, but Ptolemy had also mentioned M7 and the Coma Star Cluster (Mel 111) as early as 138 AD.
www.seds.org /messier/open.html   (1098 words)

 Open Clusters   (Site not responding. Last check: 2007-11-06)
Clusters of star occupy a focal position in studies of stellar evolution because they can usually be considered to contain stars that were all born at the same time.
They come in two basic types; there are open clusters like the Pleiades, which are usually young and situated near the plane of our Galaxy; and there are globular clusters, like M3, which are very old, compact and distributed in a halo around the Galaxy.
I use observations of young open clusters to investigate the evolution of rotation, magnetic activity and lithium depletion in stars that are as or less massive than the sun.
www.astro.keele.ac.uk /~rdj/pages/cluster.html   (138 words)

 Open Clusters
Open clusters (relative to globular clusters) are young clusters of metal rich Population I stars.
The cluster is believed to be in equilibrium right on the point of falling apart, which explains the loss of all low-mass members of the cluster.
Although clusters are often moved out of the galactic plane by their passage through interstellar clouds or close approaches to other massive bodies, it takes a very long time for the orbital plane to become as inclined as that of NGC 752.
www.peripatus.gen.nz /Astronomy/OpeClu.html   (2247 words)

 ScienceDaily: Open cluster   (Site not responding. Last check: 2007-11-06)
Open clusters are strongly concentrated close to the galactic plane, with a scale height in our galaxy of about 180 light years, compared to a galactic radius of approximately 100,000 light years
Motions In Nearby Galaxy Cluster Reveal Presence Of Hidden Superstructure (September 14, 2004) -- A nearby galaxy cluster is facing an intergalactic headwind as it is pulled by an underlying superstructure of dark matter, according to new evidence from NASA's Chandra X-ray Observatory.
Open cluster -- 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...
www.sciencedaily.com /encyclopedia/open_cluster   (4460 words)

 OpenClusters   (Site not responding. Last check: 2007-11-06)
As is the case with almost all open clusters, there is a red star near the center of the group — a 7th magnitude K3 giant.
This is one of the showiest open clusters in the southern sky.
Note that at the southeast end of the coat hanger's bar is the faint open cluster NGC 6802 (the dim nebulous object to the lower left).
www.belmontnc.4dw.net /openclusters.htm   (5657 words)

 Open or Galactic Clusters   (Site not responding. Last check: 2007-11-06)
Here is an image of the open cluster M50, which is 3000 light years from Earth and is about 20 light years across.
Open clusters typically contain of order 100 stars, as compared with as many as hundreds of thousands in globular clusters.
The stars in the cluster must all have approximately the same proper motion or the cluster would have dissipated over time, but stars not associated with the cluster would be expected to have more random motions.
csep10.phys.utk.edu /astr162/lect/clusters/open.html   (314 words)

 PCJ Article: "Open Space" Zoning, by Randall Arendt
The remaining open space is permanently protected under a conservation easement co-signed by a local conservation commission or land trust, and recorded in the registry of deeds.
As "open space zoning" is based upon the technique of "clustering," these two terms are used interchangeably throughout the rest of this article.
The beauty of open space zoning is that it is easy to administer, does not penalize the rural landowner, does not take development potential away from the developer, and is extremely effective in permanently protecting a substantial proportion of every development tract.
www.plannersweb.com /articles/are015.html   (2996 words)

 open cluster concept from the Astronomy knowledge base   (Site not responding. Last check: 2007-11-06)
Open clusters line the Galactic plane, in contrast with globular clusters, which are members of the Galaxy's halo or thick disk.
Depending on their age, stars in open clusters "peel off" from the main sequence at different points (the higher the turnoff point, the younger the cluster).
Coma open cluster (6 facts) - Open cluster similar to the Hyades in overall binary frequency.
www.site.uottawa.ca:4321 /astronomy/opencluster.html   (209 words)

 open cluster
An older name for such groupings is galactic clusters because they are found mostly in the disk, and especially the spiral arms, of this and other disk galaxies.
The stars in open clusters have formed together within the same interstellar cloud; indeed, in many diffuse nebulae, the birth of new open clusters can be seen taking place.
As open clusters drift along, some of their members escape due to velocity changes in mutual closer encounters, tidal forces in the galactic gravitational field, and encounters with field stars and interstellar clouds passing their way.
www.daviddarling.info /encyclopedia/O/opencluster.html   (256 words)

 Open Cluster Celebration
Open clusters are groups of perhaps 10 to a few thousand stars.
The stars inside of open clusters are young to middle aged, and the groups are among the youngest of any groupings of stars in the sky.
The open clusters we will be viewing this week (weather permitting, of course) are the objects M35, M36, M37, and M38.
www.tmclark.com /Starwatch/3_15.html   (640 words)

 APOD Index - Stars: Open Clusters
Two types of star clusters are visible in our Milky Way Galaxy: open clusters and globular clusters.
Open clusters like M50, shown above, typically contain hundreds of stars, many of which are bright, young, and blue.
Open clusters tend to have irregular shapes and are mostly found in the plane of our Galaxy.
antwrp.gsfc.nasa.gov /apod/open_clusters.html   (391 words)

 Open Clusters and Galactic Structure
The open cluster system is of great value for the study of The Galaxy dynamics, because they span a relatively wide range of ages, that can be determined with more precision than any other spiral arm tracer.
We explore the kinematics of open clusters using the statistical method of Sanders (1971) in order to derive the cluster stars individual membership probability as well as the cluster mean proper motion based on relatively large samples of stars.
Also, we have compiled a new Catalog of Open Clusters which updates the previous catalog of Lynga (1987) by a significative amount (more than 400 clusters) This catalog is a compact and powerful tool to study the structure of the galaxy, because it is complete containing both proper motions and radial velocities.
www.astro.iag.usp.br /~wilton   (918 words)

 Open Cluster   (Site not responding. Last check: 2007-11-06)
Open clusters are usually young (in astronomical terms), and so contain many hot and luminous stars.
The sun's original cluster met the same fate; there is no way to tell which are former members and which just happened to have been created at the same time but in a different location.
The exact timeline of this evolution is believed to vary according to the cluster's initial density: more tighly packed clusters will survive for longer, but no known cluster has lasted more than a few billion years.
www.wikiverse.org /open-cluster   (588 words)

The Open Cluster Group is an informal group of people dedicated to making cluster-computing practical for high performance computing.
We believe the adoption of clusters for mainstream high performance computing is limited by the lack of well -accepted software stacks that are robust and easy to use by the general user community
Membership is open to anyone who shares these principles and anyone who agrees to work with us in a sprit of open cooperation.
www.openclustergroup.org   (140 words)

 M11, Open Cluster
M11 is one of the most condensed open clusters in the sky.
An intriguing and tantalizing sight in binoculars, it is wonderful in a telescope, and is many observer's favorite open cluster.
M11 is also called the "Wild Duck Cluster" because of it's resemblance to a flight of wild ducks when viewed in a telescope.
www.astropix.com /HTML/D_SUM_S/M11.HTM   (160 words)

 NCKAS -Open Clusters
Open clusters NGC 869 and NGC 884, however, are doubly impressive.
The clusters are over 7,000 light years distant toward the constellation of Perseus, but are separated by only hundreds of light years.
These clusters are magnificent viewed with wide-field as a pair, or viewed separately under higher magnification and smaller field of view.
www.nckas.org /openclusters   (1812 words)

 Open Star Clusters
Open clusters are much smaller than globular star clusters, containing only a few tens or hundreds of stars.
Open star clusters are important because planets probably form at the same time around some of these stars.
Unfortunately it is hard to watch open star clusters form because spiral arms are surrounded by clouds of gas and dust.
www.historyoftheuniverse.com /openstcl.html   (133 words)

 Star Clusters
Spectroscopic study of globular clusters shows that they are much lower in heavy element abundance than stars such as the Sun that form in the disks of galaxies.
Open (or galactic) clusters are physically related groups of stars held together by mutual gravitational attraction.
Open clusters populate about the same regions of the Milky Way and other galaxies as diffuse nebulae, notably spiral arms in disk galaxies, and irregular galaxies, and are thus found along the band of the Milky Way in the sky.
www.seds.org /messier/cluster.html   (574 words)

 Open Cluster NGC1245 - Star Clusters - Digital Images of the Sky   (Site not responding. Last check: 2007-11-06)
The Open Star Cluster NGC 1245 has a distance of about 2.5 kpc in the direction of the constellation Perseus.
The relative large number of these evolved stars is a hint for the old age of the cluster.
Open Cluster Data 5th Edition (Lynga 1987) at CDS Strasbourg.
www.allthesky.com /clusters/n1245.html   (231 words)

M35, at left here, is a spectacular large open cluster containing about 200 stars located in Gemini.
It is accompanied by a jewel-like smaller companion, open cluster NGC 2158, seen at the lower right of the photo.
The smaller cluster is easily resolved in the Astro-Physic's 130 EDT refractor, but many people mistake it for a comet when they observe M35 if they have not seen it before and are not familiar with it.
www.astropix.com /HTML/B_WINTER/M35.HTM   (158 words)

 M-50, Open Star Cluster   (Site not responding. Last check: 2007-11-06)
G.D. Cassini reported finding a nebula in the general area sometime before 1711, and thus he was possibly the first observer of M-50.
Messier rediscovered it in April, 1772, and recognized it as a star cluster.
Cluster, very large, rich in stars, westward compressed, extended, stars of magnitude 12 to 16."
www.kopernik.org /images/archive/m50.htm   (171 words)

 Open Site in TutorGig Encyclopedia   (Site not responding. Last check: 2007-11-06)
Open Cluster NGC 2360 or simply NGC 2360 is an open cluster in the Canis Major constellation.
Open reduction refers to open surgery to set bone s, as is necessary for some fracture s.
Open Market Operations are the means by which central bank s control the liquidity of the national currency...
www.tutorgig.com /es/Open+Site/14   (858 words)

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