Download Open Clusters

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Open Clusters
Allan Harrell
Edgar Toledo
Tenaya Pusley
Carmen De Martis
What is a star?

A giant ball of gas
 Hydrogen
 Emits light
 Different colors and
sizes
How do stars form?

Form from clouds of
dust and molecular
hydrogen
 Gravity collapse
Why doesn’t a star continue
collapsing?

Hydrostatic
Equilibrium
 Gravity pushes in….
 Pressure pushes
out…
 Create an
equilibrium
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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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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
Fusion is important!!
1. Fusion
creates energy
2. Energy
raises temperature
3. Temperature
4. Faster
makes atoms move faster
moving atoms increase pressure
5. Pressure
fights against gravity
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http://www.star.ucl.ac.uk/groups/hotstar/images/life_cycle.jpg
“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.
-
Fuel fusion
http://physics.uoregon.edu/~jimbrau/BrauImNew/Chap21/FG21_05.jpg
“Supernova explosion”
http://imgsrc.hubblesite.org/hu/db/2004/29/videos/d/stills/3/image.jpg
“What happens after death”
It either becomes a:
Black hole
or a
Neutron star.
http://dante.physics.montana.edu/ns_interior.jpg
“Black Hole”
http://www.wvp-consulting.com/astronomy/images/blackhole.jpg
Observations:
Used
the Lick Nickel 40
inch telescope
Observed remotely with
the help of Elinor Gates
Took images of 4 open
clusters
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http://www.ucolick.org/graphics/nickel_lg.jpg
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:
Y=brightness
“Freeze
frame” of a
cluster
 Reveals age
of cluster
 Made by
computer

X=color and temp.
Which Isochrone Matches the CMD?
A.
B.
This one! Correct! :)
(CMD)
(ISOCHRONE)
How to calculate the distance:
Due to dust
Apparent Mag.
(from CMD)
0.2
(
m-M+5-Ar
)
d=10
Distance
Absolute Mag.
(from isochrone)
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M11
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
•What I found out :
 5095 light years from the earth
1.6 billion years old
My Color
Magnitude
Diagram
Open
Cluster
NGC6939
NGC 6819
Apparent Diameter: 5 arc min.
“NGC 6819”
Open star cluster
According to my results:
-It is about 3/4 of the Earth’s lifetime old.
-It is about 7,603 light years away from us.
-Has a metallicity of about 2%---like Sun
“Isochrone”
“CMD”
for NGC 6819
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)
Isochrones
Puzzles from NGC 6791
It’s really old
 Metal rich

NGC 6705
NGC 6791
NGC 6819
Sun
NGC 6939
We would like to thank:
CFAO
Laura
Chomiuk
Kathy Cooksey
Daisy Corral
Liz Espinoza
Emily Freeland
Elinor Gate
•John Martin
•Hilary O’Bryan
•Jay Strader
•Gene Switkes
•Vay Hoang