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Unformatted text preview: e stars, then finding the main sequence of that
We then compare the apparent magnitudes of the
cluster main sequence to the absolute magnitudes of
the standard main sequence.
This will give us the difference between the absolute
and apparent magnitudes which we can use in the
distance formula. Clusters dpc = 10 m− M +5 5 Astronomers work out the age of a
star cluster also by plotting its stars
on an H-R diagram.
By finding the mass of the stars
that are just leaving the main
sequence, we can calculate the
age of the cluster. The older a cluster becomes, the
further down the main sequence
the turn-off point will be.
Clusters Stellar Evolution
The evolution of a medium
mass star ( 3 – 7 solar masses)
differs little from that of a solar
mass star until after it leaves
the main sequence.
In the red giant stage, helium
ignition proceeds smoothly.
There is no Helium flash.
As a result the star proceeds
smoothly along the H-R
diagram. Stellar Evolution
Another difference is that a low mass star like our
Sun does not compress its core sufficiently to fuse
elements beyond helium.
elements However a star of more than about 3 – 4 solar
masses can become...
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- Fall '11