Star ClustersTo add further background information on star clusters and determining their ages, we first need a little info on star clusters themselves - here is a clip from Crash Course Astronomy, by a Phil Plait from BadAstronomy.com.
Using H-R Diagrams to determine star cluster ageThe age of star clusters can be estimated by examining a plot of star brightness (magnitude) against colour (temperature), this plot is known as a H-R diagram. Below are a few examples and variations of these plots.
The H-R diagram plot is used to reveal which stars are still on the main sequence - since we are able to easily identify how long a star is able to burn its hydrogen supply in its core before it moves onto the next stage of its lifecycle towards death. These are main-sequence lifespans and are easily found in tables (link 1) (link 2). You can google for more detailed tables with smaller intervals of temperature.
Note that in the upper left corner of the plot, the stars in this cluster have begun to peel away from the main sequence.
Discussion:1)Which cluster is the oldest? How old? Get answer to your question and much more 2)Which cluster is the youngest? How young? Get answer to your question and much more 3)How do the ages of these star clusters compare with the age of the galaxy (or theage of the universe)? Comment on any differences. Get answer to your question and much more 4)Which cluster is the most distant, and which is the closet? Comment on wherethese clusters tell us about the extent of the Milky Way galaxy. Get answer to your question and much more Recommended textbook solutionsIntroductory Astronomy3rd EditionAbe Mizrahi, Edward E. Prather, Gina Brissenden, Jeff P. Adams 429 solutions Astronomy1st EditionAndrew Fraknoi, David Morrison, Sidney C Wolff 972 solutions Foundations of Astronomy11th EditionMichael A. Seeds 290 solutions The Cosmic Perspective ( Edition)8th EditionJeffrey O. Bennett, Mark Voit, Megan O. Donahue, Nicholas O. Schneider 1,638 solutions Which cluster is the oldest?A team of astronomers using the Gemini-South telescope has discovered one of the oldest stellar clusters in the Milky Way. The team's results date the globular cluster, named HP 1, at about 12.8 billion years, making its stars among the oldest ever found in our Galaxy.
Which cluster has the oldest stars?Globular clusters contain several thousand to one million stars in spherical, gravitationally-bound system. Located mostly in the halo surrounding the galactic plane they comprise the oldest stars in the galaxy.
What is the youngest globular cluster?Within age uncertainties, Segue 3 appears to be the youngest globular cluster so far known in the halo, or in the whole Galaxy altogether.
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