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Equation for Solid Planet Structure

  1. Jan 15, 2007 #1
    I'm looking for an radial equation to find the pressure or density of the interior of a moon or rock planet. It would involve Young's modulus or Poisson's ratio or something like. Any help?
  2. jcsd
  3. Jan 15, 2007 #2

    Chris Hillman

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    Well, you should probably start with something more basic: the equation of hydrostatic equilibrium. This is relevant to models in which you model a planet or star as a ball of fluid, but also to models in which you model it as an (isotropic, inhomogeneous) elastic medium. I take it you are looking for a Newtonian model? There are many books on Newtonian models of stellar structure, also many books on geophysics.
  4. Jan 16, 2007 #3
    There are books on geophysics? Really? Your reply is kind of a downer. I've solved hydrostatic eq'ns for spheres and I'm looking for a next thing to do.
  5. Jan 20, 2007 #4


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    Hi Helios!

    Maybe this one is what you are looking for: http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1980LPSC...11.1999A&data_type=PDF_HIGH&type=PRINTER&filetype=.pdf [Broken]
    I'm not so good at math and physics, so I don't really understand everything in the text. If you can use the formulas in the text to find density (and temperature), please tell me how!
    Last edited by a moderator: May 2, 2017
  6. Jan 20, 2007 #5

    Chris Hillman

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    The next thing after fluid balls in hydrostatic equilibrium?

    Hi, Helios,

    Sorry if I underestimated your previous experience. Should I infer from your handle that you are particularly interested in stellar interiors? Would adding rotation whet your appetite? If so, if you know about McLaurin spheroids, I suppose the obvious next question is: have you studied Chandrasekhar, Selected Papers, esp. Vols 1, 4? That should keep you happy for a while!
    Last edited: Jan 20, 2007
  7. Jan 28, 2007 #6
    Hi Chris. I have Chandra's book "Stellar Interiors" and that's it. Out of it I'm trying to understand his explanation of composite polytropes. I don't get it and there are no examples.
    Anyway I'm looking for a solid planet equation that might resemble Emden's eq'n.
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