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Astronomy - Main sequence and red giants

  1. Sep 16, 2011 #1
    What is the main reason why there are so many more stars in the Main sequence in comparison with the number of red giants?
  2. jcsd
  3. Sep 16, 2011 #2


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    Staff: Mentor

    I'd guess that the main sequence for moderate-low mass stars takes billions of years while the red giant phase is much much shorter. On the order of hundreds of millions to a billion or so years at most I think.
  4. Sep 16, 2011 #3
    I'd agree with Drakkith on that point, plus not all main sequence stars will ever be red giants. They have to be born with 0.5 to 10 Solar masses worth of matter, or have it added to them by a companion during their lives. Akin to finding a four leaf clover on one specific day of the year.
  5. Sep 18, 2011 #4
    Thanks for your replies!

    I think my question have been answered now.
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