Question: how do you map an explosion of a neutron star? Do we have satellites out there or are we using EM waves to predict what happens?

Alice Harpole answered on 14 Mar 2016:

The particular explosions that I look at have the more technical name ‘Type I X-ray Bursts’. They occur on the surfaces of some neutron stars which are in orbit about stars of a similar mass to our Sun. We see them as very bright flashes of X-ray radiation. From the way the radiation we measure suddenly increases then slowly dims again, and from the other things we know about the neutron star, scientists have worked out that these flashes are likely to be due to the ignition of nuclear fusion at a point in the liquid ocean layer on the surface of the star, then this fusion burning very quickly spreading throughout the entirely ocean before it engulfs the star entirely. The exact mechanism is still not clearly understood, so in my work I’m creating simulations to try and understand it better.

We have seen these events using space-based X-ray telescopes, e.g. the Rossi X-ray Timing Explorer (RXTE) has spotted quite a few. They tend to occur on the surface of each star every few hours to days, so although there are only about 40 or so observed sources, we have many observations of them over the last 40 or so years (which for astrophysical events is actually pretty good going!).