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White dwarfs and the age of the universe

  1. Feb 20, 2007 #1

    I'm doing a bit of research into white dwarfs and cosmochronology as part of my uni course, it seems like a fantasticaly interesting field but i've got a couple of questions which i haven't yet been able to find answers to.

    Firstly, several papers i have read refer to a luminosity of log(L/Lsolar) = -4.5 when refering to ages on a luminosity/Age graph. I assume this is reffering to a specific point at which stars with a lower luminosity have not been found and so corresponds to the oldest stars?

    Secondly I am unclear about the conditions which lead to convection zones being formed in the envelope and what governs their progression through the atmosphere to the degenerate core. I understand the effect they have on the overall cooling rates but not why they should only be present below specific temperatures.

    If anybody could shine any light on these i would be in your debt

    Many thanks Phil
  2. jcsd
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