1. The radius of a star that has a surface temperature of 28900k and is 10000 ties brighter than the sun is___Rsun? I was told that the answer is 4.027 Rsun but im not sure how to get the answer
2. The observer wavelength of a spectral line from a nearby star is 3.33x10^-7m. This spectral line should have a wavelength of 3.66x10^-7m. Therefore this satr has a velocity of ____km/s?
3. A star that has a parallax of 0.020 arcseconds is ___lightyears away from the earth? I have 16 but Im not sure