B What kind of supernova do binary neutron stars produce?

[Irfan Nafi]

I was wondering if a binary system of neutron stars were to collide what kind of nova or supernova would it be. Is it different if the final mass of the neutron star is sufficient enough for a black hole or if it still a neutron star?

 

[Simon Bridge]

iirc A supernova how you get neutron stars.

 

[Ken G]

It likely depends on the maximum mass of a neutron star, which is not well known. Their minimum mass is 1.4 solar, and they are often near that, so putting two together could get up near 3, and that's thought to be about the limit, but there might also be mass lost in the resulting supernova. Probably we'll need observations. The supernova can depend on whether it makes a black hole or not-- for example, there is a situation where if everything falls into the black hole, you don't get a supernova at all, because nothing gets out. I don't think that would happen with merging neutron stars though, I think something would come out beyond just the gravitational waves.

 

[|Glitch|]

I was wondering if a binary system of neutron stars were to collide what kind of nova or supernova would it be. Is it different if the final mass of the neutron star is sufficient enough for a black hole or if it still a neutron star?

The merger or two neutron stars would not produce a supernova, although the electromagnetic emissions from such a merger may have a similar, but much dimmer, appearance. If the combined mass of both neutron stars exceeds the Tolman-Oppenheimer-Volkoff limit of approximately 3.0 solar masses then a black hole would be formed as a result of the merger. It is also suspected that such a merger would produce gravity waves and may be one source for short duration (less than 2 second) gamma-ray bursts.

Sources:
Opacities and Spectra of the r-process Ejecta from Neutron Star Mergers - arXiv 1303.5788
Radiative Transfer Simulations for Neutron Star Merger Ejecta - arXiv 1306.3742
The long-term evolution of neutron star merger remnants - II. Radioactively powered transients - arXiv 1307.2943