Open Clusters

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Open Clusters

• Allan Harrell
• Edgar Toledo
• Tenaya Pusley
• Carmen De Martis

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What is a star?

• A giant ball of gas
• Hydrogen
• Emits light
• Different colors and sizes

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How do stars form?

• Form from clouds of dust and molecular hydrogen
• Gravity collapse

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Why doesnt a star continue collapsing?

• Hydrostatic Equilibrium
• Gravity pushes in.
• Pressure pushes out
• Create an equilibrium

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What are open clusters?

• Young stars
• Same chemical composition
• Same Age
• Distance
• Bound by gravity
• Form in spiral and irregular galaxies

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The Main Sequence
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About Main Sequence Stars

• Stars spend most of their life in the main
  sequence, about 90
• Our sun is 5 billion years into its main sequence
• The larger the star, the less time it will spend
  on the main sequence
• Main sequence stars maintain brightness and
  energy through fusion

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Photosphere
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?
?
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Fusion is important!!

• Fusion creates energy
• Energy raises temperature
• Temperature makes atoms move faster
• Faster moving atoms increase pressure
• Pressure fights against gravity

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(No Transcript)
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http//www.star.ucl.ac.uk/groups/hotstar/images/li
fe_cycle.jpg
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What happens in a high mass star?

• Shorter lifetimes
• Consumes fuel faster
• Fuses more elements.
• Fusion of iron consumes energy instead of giving
  off energy.

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Fuel fusion
http//physics.uoregon.edu/jimbrau/BrauImNew/Chap
21/FG21_05.jpg
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Supernova explosion
http//imgsrc.hubblesite.org/hu/db/2004/29/videos
/d/stills/3/image.jpg
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What happens after death

• It either becomes a
• Black hole
• or a
• Neutron star.

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http//dante.physics.montana.edu/ns_interior.jpg
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Black Hole
http//www.wvp-consulting.com/astronomy/images/bla
ckhole.jpg
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Observations

• Used the Lick Nickel 40 inch telescope
• Observed remotely with the help of Elinor Gates
• Took images of 4 open clusters

http//www.ucolick.org/graphics/nickel_lg.jpg
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CCDs

• Basic tools of astronomical imaging
• Grids of light buckets
• Colorblind
• 3 different filters allow us to see color (red,
  green, and blue)
• Same as the digital cameras that you may own

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Isochrones

• Freeze frame of a cluster
• Reveals age of cluster
• Made by computer

Ybrightness
Xcolor and temp.
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Which Isochrone Matches the CMD?
A.
B.
This one! Correct! )
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(CMD)
(ISOCHRONE)
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d100.2 ( m-M5-Ar )
How to calculate the distance
Due to dust
Apparent Mag.
(from CMD)
Absolute Mag.
Distance
(from isochrone)
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M11, The Wild Duck Cluster
i
hh
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M11
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Color Magnitude Diagram

• y-axis brightness
• x-axis color
• M11
• Around 2000 parsecs
• Around 6000 light years
• Mostly main sequence
• stars
• 200 million years old

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NGC6939

• What I found out
• 5095 light years from the earth
• 1.6 billion years old

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My Color Magnitude Diagram
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Open Cluster NGC6939
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NGC 6819Apparent Diameter 5 arc min.
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NGC 6819Open star cluster
According to my results -It is about 3/4 of
the Earths lifetime old. -It is about 7,603
light years away from us. -Has a metallicity of
about 2---like Sun
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Isochrone CMD
for NGC 6819
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NGC 6791

• Observed and recorded data for NGC 6791
• 7.6 billion years old
• Looking at isochrones
• 4972 parsecs (3.26 light years 1 parsec)

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Isochrones
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Puzzles from NGC 6791

• Its really old
• Metal rich

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NGC 6705
NGC 6791
NGC 6819
Sun
NGC 6939
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We would like to thank

• CFAO
• Laura Chomiuk
• Kathy Cooksey
• Daisy Corral
• Liz Espinoza
• Emily Freeland
• Elinor Gate

• John Martin
• Hilary OBryan
• Jay Strader
• Gene Switkes
• Vay Hoang