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Unformatted text preview: nt may contain sufficient
mass to form a star.
This is how multiple stars can form.
However some clouds are so massive that they
may form dozens or even hundreds or thousands
These “families” of stars are known as “clusters”.
There are two types of clusters:- Open Clusters
and Globular Clusters.
Globular Open Clusters
Open clusters generally
contain only a few
They lack and regular
structure and they are
generally Many very young open clusters are still surrounded by
nebulosity left over from their formation.
nebulosity Globular Clusters
are huge balls of
stars which can
contain up to 2
Diameter ~100pc They are composed
mostly of very old stars
mostly Globular Clusters
Since they are
so large and
they can be
seen over large
Star clusters are very important to astronomers. Since
they all formed at the same time from the same cloud of
gas, their stars are all the same age and they are all at
the same distance. This enables us to find both the distance to the cluster
and its age. Clusters
We find the distance to the cluster by plotting an HR
diagram of the cluster, using the apparent magnitudes
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This note was uploaded on 08/27/2013 for the course ASTRO 1402 taught by Professor Clark during the Fall '11 term at Texas Tech.
- Fall '11