Astronomy

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I have two stars A = 7150K and B = 4850K.A is 20 times brighter than B.
Assuming L/Lv is the same for both stars find the ratio ofthe radii of A and B.
I have the equation R/R= (L/L)^1/2(T/T)^2.
I can do this for each star in terms of solar masses but i am unsure which temperature goes in the numerator/denominator?
Is (L/Lv)^1/2 sqr root 20?

  • Astronomy -

    luminosity is proportional to r^2*temp^4
    so if are comparing r, then

    r^2 prop Luminosity/T^4

    so in your

    Ra/Rb= sqrtLa/Lb) * (tb/ta)^2
    = sqrt (20) * (4850/7150)^2

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