• Question: does a supernova eventually become a black hole?

    Asked by sevvalA to Heather, Helen, Hugh, Jane, Julian on 14 Nov 2014. This question was also asked by CharlotteW.
    • Photo: Julian Onions

      Julian Onions answered on 14 Nov 2014:

      Only some times, generally it depends how massive the star is when it explodes.

      If its less than about 8 solar masses (8 x the mass of the sun) then it probably won’t become a black hole. Towards the end of its life a star tends to loose a lot of material, so it decreases in mass, so even big stars can fall below the limit.

      After it goes supernova – and it has to be a biggish star to do that, our own sun won’t for instance, then it depends how much is left over after the explosion.

      If there is just a small amount, say about the mass of the sun, it will form a white dwarf. If its up to about 3 solar masses it will make a neutron star, and above that probably a black hole, although we don’t know precisely the exact mass required.
      So – really it all depends how big it was to start with, and how much it lost before and during the time when it went bang!

    • Photo: Helen Johnson

      Helen Johnson answered on 16 Nov 2014:

      As Julian says, only if the star was very large to begin with. Our Sun definitely won’t form a black hole. Some black holes aren’t formed from stars at all – for example the super massive black holes at the centre of galaxies.

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