Transcript Globular Clusters

COSMOS 2005 Cluster 7 Presents:
by Amanda Loo &
Catherine Russell
Outline
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What is a globular cluster?
How do stars evolve?
Observing
Filters, tri-color image
Age of and Distance to M13
Age of the Universe
What is a globular cluster?
A globular cluster is a…
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very dense
extremely old
super bright
gravitationally bound
populated (millions of stars)
collection of stars found in the
halo of our galaxy.
Hertzsprung-Russell Diagrams
Bright
SUN
Dim
Hot
Cold
Asymptotic Giant Branch
Helium Flash
Red Giant Branch
Horizontal Branch
Evolution of a 1 Solar Mass Star
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.
Color Magnitude Diagrams
Bright
•Specialized H-R Diagram
•Converts luminosity to apparent
magnitude (how bright it looks)
•Converts temperature to color
(like heating a stove)
Helium Flash
Luminosity
Magnitude
Bright
Red Giant
Branch
Horizontal
Branch
Turnoff from
Main Sequence
Dim
Hot
Cold
Temperature
Dim
Bluer
Color
Redder
Isochrones
• Used to find age and distance
• Difficult to use
• Horizontal Branch not modeled
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 410 thousand light years away.
– Literature says about 24,000 light years.
Thanks to:
• Kirsten Howley
• Andrea Michels
• Becca, Molly, Jared
• open clusters group
• Ellie Gates
• Hilary & Greg O’Bryan
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• 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