We then compare the apparent magnitudes of the

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Unformatted text preview: e stars, then finding the main sequence of that cluster. 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 This 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. the Clusters Clusters Stellar Evolution Stellar Evolution Medium­Mass Star The evolution of a medium The mass star ( 3 – 7 solar masses) differs little from that of a solar mass star until after it leaves the main sequence. the In the red giant stage, helium In ignition proceeds smoothly. There is no Helium flash. There As a result the star proceeds As smoothly along the H-R diagram. diagram. Stellar Evolution Stellar Evolution Medium­Mass Star Another difference is that a low mass star like our Another Sun does not compress its core sufficiently to fuse elements beyond helium. elements However a star of more than about 3 – 4 solar However masses can become...
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