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Entropy of a star

  1. Aug 22, 2004 #1
    How is the entropy of a star like the sun or a neutron star calculated?
     
  2. jcsd
  3. Aug 31, 2004 #2
    to calculate the thermodynamical entropy, I suppose that you could use the famous Boltzmann entropy equation:
    S=k*ln W
    W is the number of distinguishable arrangements of atoms/molecules.
    If you are able to figure out W, work done!
     
    Last edited: Aug 31, 2004
  4. Sep 1, 2004 #3
    The entropy of a black hole is [tex]S=\frac{Akc^3}{4hG}[/tex] where A is the area of the black hole, k the Boltzman's constant, h the Planck's constant, c the speed of light and G the gravitational constant
    (http://nrumiano.free.fr/Estars/bh_thermo.html)

    I'm not sure you can use the same formula for a (neutron) star though.

    See also: http://www.madsci.org/posts/archives/sep99/937295445.As.r.html

    (Google is the answer to a lot of questions!!)
     
    Last edited: Sep 1, 2004
  5. Sep 1, 2004 #4

    russ_watters

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    Staff: Mentor

    Since we know the power output of the sun and we know the enthalpy and entropy of a fusion reaction, its just an easy ratio.
     
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