Download Binary Star Systems

Jody’s Physics Research Project
A study on the orbital velocities of a
binary star system orbited by a single
star.
Gravity
Some think that money makes the world go
‘round, but they’re wrong. It’s gravity!
 Gravity keeps us on the ground. Gravity
keeps the earth rotating around the Sun.
And, gravity allows us to see comets up close
and personal (not always a good thing).
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Binary Star Systems
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“Half of all stars in the
sky are members of
binary systems.”
Binary star systems
consist of two stars
that orbit around a
point called the center
of mass.
Common Orbits
One Theory
Collapsing Nebula
Consider...

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Multiple star systems exist. They are just like binary
star systems, but with more stars.
It’s difficult to tell whether a binary system may have
a third star orbiting far away. This star is still
effected by the systems gravity, but it may take
hundreds of years to pass through one orbit.
For example, astronomers hypothesize that our Sun
may have a “stellar companion” of low mass
beyond Pluto. Cool huh!
My Project

I am interested in
looking at a binary
system that is orbited
by a single star.
Specifically, I want to
explore the stability of
the orbit (by looking at
the velocity) as it
depends on the
distance.
BA
A
B
A
The Formula

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F=Gm1m2/r²
F=ma=mv²/r
Set them equal to each
other. Do math.
v=½(Gm/r)^½


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m=3.00e24kg
mB=6.00e24kg
G=6.672e-11Nm²/kg²
r=2.5e8m
Important Graph
Orbit Deviation
800
700
Standard Deviation
600
500
400
Series1
300
200
100
0
0
2
4
6
Distance (million meters)
8
10
12
Conclusion
My hypothesis was that the variation of the
velocities would be less as the two systems
were placed further apart.
 I’m kind of wrong. Looking at the graph,
there are two places where the data is
inconsistent with this theory.

Why?
Well, I am using a computer simulation. It
computes velocities but as it continues
through the simulation, it becomes less
accurate (or something like that).
 The second reason could be experimenter
error. I noticed the orbital graphs were not
repeating. So, I stopped the simulation when
I guessed I had gathered enough data.

Future Plans
I’ll probably try to fix these problems and try
again. Or…
 I would like to try my original hypothesis
which was similar to this one except with two
binary systems.
 I’m still fascinated by multiple-star systems
and would like to continue in that area. It’s a
shame I can’t measure the real thing!!

Jody’s Physics Research Project
Thank you!