Is it true that stars start with a rocky core, then collect hydrogen by the gravity of that rocky core, just like planets collecting materials?

  • $\begingroup$ I wouldn't say it's impossible that a large rock found its way to the center of a collapsing nebula, but as Rob answers below; no, it's not needed. $\endgroup$
    – Logan
    Commented Jul 18, 2016 at 16:32
  • $\begingroup$ And there was no "rock" when the first star in the universe formed :) $\endgroup$
    – Lake
    Commented Jul 20, 2016 at 11:48

1 Answer 1


No, stars do not have a rocky core. They start as clouds of gas, become gravitationally unstable and collapse.

Some planets are thought to start this way too - though probably not the ones in our solar system, because the outer three three giant planets have solid cores and Jupiter is likely to also. The two modes of giant planet formation are reviewed in detail by D'Angelo et al. (2010).


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