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Calculating solar mass using luminosity

  1. May 12, 2005 #1
    Okie dokie, I searched the web and found L=M ^ 3.5 (luminosity equals mass to the power of 3.5). But, I'm pretty clueless on anything beyond Algebra I. How do I solve for M if I know L? [If the answer can be expressed in Visual Basic syntax, all the better.]

    I also read several caveats that said the above formula works best for main sequence stars. Does anyone know of better of formula for sub-dwarfs, dwarfs, giants, and super giants? I'm pulling my numbers from a sub-set of the Hipparcos data. So, from absolute magnitude, I can calculate luminosity, but I get stuck after that.

    My goal is to calculate solar mass and plug that into Accrete so I can create a fictional but semi-realistic star atlas for hard sci-fi games.

    Along a similar line, I've seen some sites that says Accrete is fairly dated as far as solar system modelling goes. Has anyone written a successor to Accrete that is available to the public?
    --
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  2. jcsd
  3. May 12, 2005 #2

    ohwilleke

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    A scientific calculator should be able to find the 3.5th root of luminosity without difficulty. I would imagine that the formula would be something along the line of L^-3.5=M, but I'm not a Visual Basic user. I also suspect that you could simply find a direct list of stellar masses in any number of references.
     
  4. May 12, 2005 #3

    Chronos

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    Use a logarithm table. Powers and roots are simple when working with log values.
     
  5. May 12, 2005 #4

    ohwilleke

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    Good point Chronos. So you would start with X=Log(L)/3.5
    Then M=INV LOG(X).
     
  6. May 12, 2005 #5
    Thanks for the prompt replies, guys. I'll give them a try. The list of stellar masses has merit, but I need to populate 59,000 solar systems and most lists only have a handful of stars. But, I can use them to check my math now that I have something to work with.
    --
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  7. May 12, 2005 #6

    tony873004

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    M=L^(1/3.5)

    But what units are you using for M and L?
     
  8. May 13, 2005 #7
    Mass of Sol = 1 and Luminosity of Sol = 1. So a star with an Absolute Magnitude of zero whould be 100 times brighter than Sol.
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