Spica is a bright star with apparent magnitude in the V filter mv=.98 and a parallax angle of 0.0125 arcsec. Thus, Mv= -3.54. Spica has an apparent magnitude in the B filter mB=.68. Thus, the color index B-V= -0.3
Q) The color index of another bright star in our summer sky, Antares, is B-V=1.67. Is Spica hotter or cooler than Antares? Explain your answer (you should include some discussion of the properties of blackbody radiators in your answer).