Re: Two neutron stars on a collision course?

On 2008-03-09, Crown-Horned Snorkack <chornedsnorkack@[EMAIL PROTECTED]
> wrote:
> When a neutron star fills and spills over its Roche lobe, some of the
> escaping matter falls towards the other neutron star or black hole,
> but some escapes outwards. But the part which escapes on the outer
> side is not at infinity! It is bound, on a circular orbit, pretty deep
> in the gravity well of the (old or new) black hole.

Yes, some will.  As I recall we were originally talking about matter
that did actually escape, though.  Certainly the accretion disk will
have some strange nuclear species in it.


> IIRC, tritium releases 18 keV per decay - half of which goes away with
> neutrino.

The neutrino doesn't go away - the thought experiment was an isolated
system.  If there's unobtainium strong enough to contain degenerate
neutron matter I'm sure it would have to contain neutrinos too.

I did get the energy of tritium decay wrong, though.  The final
conclusion still stands - the energy of tritium decay is amply enough
to trigger a state in which nuclear interactions are common and in
which tritium will not make up much of the equilibrium mix.


> It takes a lot of energy to induce fission of lead 208. Even thorium
> 232 is pretty resistant to induced fission!

It has to be more than merely "pretty resistant" in a dense soup of
nuclei and other particles with energies in the MeV range.  The
question is not how long they will last (which will be very short
indeed for any particular nucleus), but how commonly they will form.

Which nuclei will fuse to form lead-208, and how frequently compared
with other nuclei?


- Tim