Table of Contents
Why are globular clusters important?
Globular clusters are densely packed collections of ancient stars. Roughly spherical in shape, they contain hundreds of thousands, and sometimes millions, of stars. Studying them helps astronomers estimate the age of the universe or figure out where the center of a galaxy lies.
What are the two main star clusters?
The two types are open (formerly called galactic) clusters and globular clusters.
Why are clusters of stars so useful for studying stellar evolution?
What is the main reason astronomers find CLUSTERS of stars so useful in studying stellar evolution? Since stars in a cluster are of similar age and composition, clusters provide a good way to study the effects of mass on how stars develop.
Why do stars tend to form in groups?
The sinks (stars) tend to collect together into small groups or mini-clusters, because they tend to form together in regions of high density, and because they also tend to fall in toward each other as they accumulate mass. The more massive stars accumulate more mass at the expense of the low-mass objects.
Do star clusters have planets?
Astronomers have found two planets smaller than three times the size of Earth orbiting sun-like stars in a crowded stellar cluster approximately 3,000 light-years from Earth in the constellation Cygnus.
Why are clusters important in astronomy?
Star clusters are particularly important because they allow astronomers to check models of stellar evolution and the ages of stars. They therefore share the same initial metallicity so any effect of this on stellar evolution is effectively the same for the members of the cluster.
What is the meaning of cluster of stars?
Definition of star cluster : a relatively compact group of stars forming a gravitating unit and containing either not more than a few hundred stars or tens of thousands of stars.
Why do stars clusters provide excellent tests?
Why do star clusters provide excellent tests for theories of stellar evolution? The stars in any particular cluster formed at roughly the same time from the same primary material and under the same environmental conditions. What is the force that keeps a main sequence star from blowing apart?
What is the relationship between stars in a cluster?
Star clusters are groups of stars which are gravitationally bound. Two distinct types of star cluster can be distinguished: globular clusters are tight groups of hundreds of thousands of very old stars, while open clusters generally contain less than a few hundred members, and are often very young.
How do stars form in clusters?
The simplest idea is stars form into clusters when a giant cloud of gas and dust condenses. The center of the cloud pulls in material from its surroundings until it becomes dense enough to trigger star formation. From this study, they discovered the stars on the outskirts of the clusters actually are the oldest.
How can I plot the position of stars in a cluster?
Colour-magnitude and spectrum-magnitude diagrams can thus be plotted for the stars of a cluster, and the position of the stars in the array, except for a factor that is the same for all stars, will be independent of distance.
What are the characteristics of an open cluster?
Open clusters. Because of the high luminosity of their brightest stars, some open clusters have a total luminosity as bright as that of some globular clusters (absolute magnitude of −8), which contain thousands of times as many stars. In the centre of rich clusters, the stars may be only one light-year apart.
What is the shape of the most common star cluster?
Most of them appear circular and are probably spherical, but a few (e.g., Omega Centauri) are noticeably elliptical. The most elliptical cluster is M19, its major axis being about double its minor axis. Distribution of open and globular star clusters in the Galaxy.
What is the name of the star cluster observed by Hubble?
Centre of star cluster M15, as observed by the Hubble Space Telescope. Open star cluster Haffner 18. Four open clusters have been known from earliest times: the Pleiades and Hyades in the constellation Taurus, Praesepe (the Beehive) in the constellation Cancer, and Coma Berenices.