Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Primordial star formation

  1. Mar 11, 2010 #1
    Apparently, in the early universe, stars were massive - ranging up to about 500 solar masses. Furthermore the metallicity (elements other than H, He) in the early universe was effectively zero with only hydrogen, helium and trace amounts of lithium. Apparently, stars could reach large masses because much larger quantities of these H, He had to accumulate before they could come together and form a star. I was wondering if anyone knows an intuitive explanation for this? Or knows any equations which could explain this?
  2. jcsd
  3. Mar 11, 2010 #2


    User Avatar
    Science Advisor

    As you mention, the early star forming regions were devoid of metals. Metals play an important role in cooling -- 'modern' star forming regions are cooled efficiently by metals to temperatures as low as 10K. Without metals in the early days, the star forming regions were much hotter. Now, there's a special amount of mass that a system needs to acquire before it undergoes gravitational collapse -- the Jeans mass. The Jeans mass depends on temperature -- the hotter the gas the more of it you need to form an instability. So, early stars were consequently more massive than those of today.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook