(a) An astronomer obtains the spectrum of a white dwarf star, and determines that it peaks in the ultraviolet at λ = 150 nm, similar to the spectra of very luminous main-sequence stars. What is the surface temperature of the white dwarf?
(b) At the same time, the astronomer determines that the intrinsic luminosity of the white dwarf is only LW D = 0.01L⊙ (i.e. 1% of the luminosity of the Sun). As discussed in class, the luminosity and temperature of a star can be used to infer its radius. What is the radius of the white dwarf star? Express your answer in terms of the radius of the Sun, R⊙, and the radius of the earth, R⊕. (i.e., how many solar [Earth] radii is this? Or, on the other hand, what fraction of the solar [Earth] radius is this?)
Part (a) the surface temperature of the white dwarf =... View the full answer