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Homework Help: Eddington luminosity for star made out of protons

  1. Mar 30, 2010 #1
    Imagine that a star could be composed entirely of protons so that Thomson scattering by protons dominated the stellar opacity. How luminous, in [tex]L_{\odot}[/tex], would the star have to be to blow itself apart by radiation pressure?

    I know that the luminosity has to be greater than the eddington luminosity so that radiation pressure is greater that gravity.

    The equation I have for scattering for protons is [tex] \sigma_{T} = \frac{1*C^2}{6\pi}* (\frac{p^2}{(m_{p} * c^2)})^2[/tex]

    This gives me [tex]3.90 * 10^{-35} meters^2[/tex]

    The eddington luminosity equation is then [tex] L = \frac{4\pi*G*(m_{p}*C*mass of star)}{\sigma_{T}} [/tex]

    The problem is that I wasn't given a mass or radius for the star, so I'm stuck.
    Last edited: Mar 30, 2010
  2. jcsd
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