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Homework #6
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•Question 2   (1 point) In my novel Star Dragon, the characters fly to a distant binary star system, SS Cygni. SS Cygni is a type of binary system in which a white dwarf star is consuming a main sequence K star. If the average separation of the stars is 1.5 million km, and the orbital period is 6.6 hours, what is the combined mass of the stars? (Hint: it will help to immediately convert 6.6 hours to years and 1.5 million km to AU.)
 a.0.6 solar masses.  
•b.6 solar masses.  
• c.1.8 solar masses.  
•d.18 solar masses  
•e.1.3 solar masses.   
•Either solve from basic considerations (mass of KV star and white dwarf) or from Kepler’s Law:  Mass = a3/P2, with unit conversions to AUs and years.  Get 1.8 solar masses.  Cassandra should work on the board.
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