Assignment_03

# Assignment_03 - our Milky Way Galaxy now. Use the following...

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SCIENCE 238 Assignment #3 1) Two stars have the identical parallax of 0.015 arcseconds. They are 5.0 arcseconds apart in the sky. What is the distance between these two stars? (Marks: 1) 2) A visual binary star system has been observed for sixty years. In that time the two stars have completed ¼ of their orbit around “each other” (actually around their mutual centre of mass). They are just far apart enough that we can see from our observations that they are in circular orbits - they have stayed a constant 2.2 arcseconds apart since they were first observed. The parallax of the brighter star is 0.036 arcseconds. If one of the stars is a G2V star (i.e. identical to our Sun) what is the mass of its companion star? (Marks: 3) 3) Estimate the number of low and high mass stars that you expect to find in
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Unformatted text preview: our Milky Way Galaxy now. Use the following (very approximate but about right numbers) for your estimate: The Star Formation Rate in our Galaxy is approximately 1 Solar Mass per year and virtually all of this goes into making 0.5 Solar Mass stars. The Initial Mass Function, , describes the number of stars formed at each mass and is something like: M 2.3 where M is the mass of the stars in Solar Masses and o is a constant that needs to be determined . In the lectures it was shown that the lifetime of stars is given by: lifetime 10 10 years M 2.5 If the Galaxy is 10 billion years old, how many 0.5 and 50 Solar Mass stars do you expect to find in the Galaxy? (Marks: 4)...
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## This note was uploaded on 12/06/2010 for the course SCI 238 taught by Professor Kines during the Fall '06 term at Waterloo.

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