1.  Give at least 3 ways that we could deduce that an object in the sky could be a binary star system. 
                I think the key to answering this question is understand that a binary star system is periodic. 
                Therefore some phenomena detectable by us here on Earth must also be periodic. 

   

   2.  a) Which star (A or B) has the bigger orbit?  How did you know?

                b) Which star is eclipsed (i.e., which star is behind the other) at time = 0?  star A or star B? 
                    The answer is contained entirely in the radial velocity graphs of RW Mon at the top of page 18, green book! 
                    Explain how you knew (of course!). 

                    (remember the meanings of + and - radial velocity!)

   3. a) The eclipses of RW Mon (one of which is a total eclipse and the other of which is an annular eclipse; if you don't know what annular is, look it up!) both have flat bottoms (see the light curve -- i.e., the plot of apparent magnitude of time in the Astro green book page 16 or 18).  Some eclipsing binaries, however, have light curves that have pointy bottoms (like the letter V or like an upside down teepee)  describe at least  TWO situations that would produce a light curve with pointy bottoms as opposed to flat bottoms?

b) Suppose that you have a binary like RW Mon, in which the stars are so close together that we can't see the two stars separately; therefore both stars' different spectral lines are visible only in a single superimposed spectrum. 

And clearly both sets of the different spectral lines are seen, otherwise we wouldn't have the wavelength shifts of each star and thus wouldn't have the radial velocities of each star as a function of time.  So how do astronomers (in general) know which star (the bigger or the smaller) is in front at each of the two eclipses (e.g., at phase = 0.0 and phase = 0.5 for RW Mon) that occur during one orbit period?