Blue Super giants a typical blue supergiant star (the type that explode and leave behind black holes) bas a surface temperature of 30,000 K and a visual luminosity 100,000 times that of our sun. Our sun radiates at the rate of 3.86 x 1026 W. (Visual luminosity is the total power radiated at visible wavelengths.)
(a) Assuming that this star behaves like an ideal blackbody, what is the principal wavelength it radiates? Is this light visible? Use your answer to explain why these stars are blue.
(b) If we assume that the power radiated by the star is also 100,000 times that of our sun, what is the radius of this star? Compare its size to that of our sun, which has a radius of 6.96 x 105 km.
(c) Is it really correct to say that the visual luminosity is proportional to the total power radiated? Explain.