1. by Amanda Loo & Catherine Russell COSMOS 2005 Cluster 7 Presents:

2. Outline What is a globular cluster? How do stars evolve? Observing Filters, tri-color image Age of and Distance to M13 Age of the Universe

3. What is a globular cluster? A globular cluster is a… very dense extremely old super bright gravitationally bound populated (millions of stars) collection of stars found in the halo of our galaxy.

4. Hertzsprung-Russell Diagrams SUN Bright Dim ColdHot

5. Helium Flash Red Giant Branch Asymptotic Giant Branch Horizontal Branch Evolution of a 1 Solar Mass Star

6. Observing M13 and M5 Nickel 40 Inch Reflector Telescope at Lick Observatory on Mt. Hamilton Remote observing through video conference with Ellie Gates Digital detector called a charge coupled device (CCD) CCDs can detect photons but not color so we used filters to detect photons of different wavelengths.

9. C olor M agnitude D iagrams Specialized H-R Diagram Converts luminosity to apparent magnitude (how bright it looks) Converts temperature to color (like heating a stove) Horizontal Branch Helium Flash Red Giant Branch Turnoff from Main Sequence Magnitude Bright Dim ColorBluerRedderTemperature Luminosity HotCold Dim Bright

11. Isochrones Used to find age and distance Difficult to use Horizontal Branch not modeled

12. Conclusions By fitting isochrones, we determined M13 to be 19 billion years old! –Literature says 14 billion- the same age as the universe. We also determined M13 to be between 4- 10 thousand light years away. –Literature says about 24,000 light years.

13. Thanks to: Kirsten Howley Andrea Michels Becca, Molly, Jared open clusters group Ellie Gates Hilary & Greg O’Bryan supplying teenagers with liquid nitrogen Jason Porter John Martin Kathy Cooksey Laura Chomiuk Malika Mountawakkil-Bell Monica Piñon for powerpoint tips Nick Konidaris & Jay Strader balloon blower uppers & computer donor CfAO COSMOS