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Missing low-metalicity Red Dwarves

  1. Oct 2, 2014 #1
    Our local part of the universe is apparently missing Red Dwarves that have low metallicity. As near as I understand it, if the universe began 13.8 Billion years ago, there should still be plenty of these critters still around. Does anyone know how long it takes to make the heavier metals in Red Dwarves? I understand these misers can live to be trillions of years old, so could the absence of low metal Red Dwarves place a lower limit on the age of the universe (much like the way they do in globular clusters)?
     
  2. jcsd
  3. Oct 2, 2014 #2

    Bandersnatch

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    It's not that metal-poor red dwarfs are missing, they are not. The missing ones are the metal-free ones.

    Red dwarfs never pass into helium burning stage. Their fully convective interiors mix hydrogen and helium well, never forming a dense core. Even when the energy production stops after hydrogen is exhausted, the contracting core never reaches temperatures high enough to fuse helium.
    So, they never fuse any metals themselves. All metal content must have come from earlier generations of more massive stars.
    Note that the later stages of red dwarf evolution is a model without visual confirmation - red dwarfs have too long lifespans for any of them to have passed the hydrogen burning stage.
     
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