What happens when a neutron star collides with a white dwarf?

[alvarogz]

Does it exist an accurate model about what happen when two stellar bodies collide?. I'm referring to the kind of collision between neutron stars, white dwarfs. I was wondering if that collision could produce a new kind of object. For example: a white dwarf into a neutron star, and a neutron star into a black hole.

 

[FlexGunship]

Does it exist an accurate model about what happen when two stellar bodies collide?. I'm referring to the kind of collision between neutron stars, white dwarfs. I was wondering if that collision could produce a new kind of object. For example: a white dwarf into a neutron star, and a neutron star into a black hole.

I believe that type of event is incredibly unlikely (not impossible, of course). As two stellar bodies of comparable mass approach, their v-tangents rarely cross and they usually fall into a quasi-stable mutual orbit. The one becomes the parasite of the other.

As such, I don't think that many people have spent a lot of time trying to simulate an actual impact.

I'm sure it would be interesting to see.

 

[phyzguy]

Actually, there is a class of stars called "blue stragglers" which may result from stellar collisions and mergers. In the cores of globular clusters, stars are much closer together (~ 10^5 times the density in the vicinity of the sun), so stellar collisions, especially between binary stars, become possible. Here is a starting place:

http://en.wikipedia.org/wiki/Blue_stragglers

 

[bombadil]

Stars that are born orbiting one another will eventually collide because of the loss of energy due to tidal effects and the emission of gravitational waves. The collisions of stellar remnants (neutron stars, black holes, and maybe white dwarfs) are thought to power http://en.wikipedia.org/wiki/Gamma-ray_burst#Short_gamma-ray_bursts". These are the some of the most powerful explosions in the universe in which the bulk of x-ray to gamma-ray radiation arrives at Earth in the span of a few seconds or less.

 

[SpiffyKavu]

There are plenty of simulations regarding the collision of two compact objects (white dwarf (WD), neutron star (WD), or black hole(BH)) in any combination you wish. NS-NS collisions are thought to be one source of short gamma-ray bursts, as mentioned by bombadil. WD-WD collisions can trigger a type of supernova.

Collisions with black holes will cause total tidal disruption of the companion star. The star will be torn apart by the tides raised by the BH. Some of the material will escape while the rest will simply be accreted into the BH.

But these collisions are tough to simulate. We do not have a very solid understanding of the entire interior structure of NSs, so we must use various approximations. Then, computers are used to numerically solve magnetohydrodynamics codes (charged fluid in a magnetic field) in a full general relativistic setting, due to the very strong gravity of NSs and BHs.