Re: Two neutron stars on a collision course?

On 2008-03-01, Matt Browne SFW <matt.h.browne@[EMAIL PROTECTED]
> wrote:
> What exactly will happen when two neutron stars are on a collision
> course? I think a supernova and black hole is inevitable if both
> neutron stars are very heavy. But what about smaller ones?

I was going to post about how neutron stars have a minimum mass that
would guarantee a black hole.  But being not entirely sure of that I
looked up a few recent articles, and to my surprise found one that
calculated the behaviour of a neutron star barely under the modeled
minimum stable mass, just 0.189 solar masses!

So it seems neutron stars could at least theoretically be small enough
to avoid black hole formation upon collision.


> Will they merge? Or be torn into thousands of "pieces" from the
> impact? Another theory is gamma ray bursts with huge amounts of mass
> converted into energy. Expert opinion?

I'm certainly not an expert, but with that amount of mass having that
much kinetic energy upon colliding, I'd expect at least the equivalent
energy release of a small supernova.

Total fragmentation couldn't happen even theoretically unless they
were merging at a decent fraction of lightspeed initially - the
gravitational binding energy is far too great for that.  Actual mass
conversion to energy is unlikely, but it could dissipate quite some
fraction of the kinetic energy built up as they fall into each other,
which would not be a negligible fraction of their rest mass/energy.

I think a gamma ray burst would be inevitable.  I don't know even
within an order of magnitude what fraction of the total energy it
would include.


- Tim