finally, a model bursting neutron star

 Plasma from a neighboring star gets pulled into the orbit of a neutron star, where it slams into the stellar surface( accretion), creating thermonuclear explosions. Image: NASA

 A neutron star in a cluster in Terzan 5 was monitored by several groups who claim to have viewed all phases of thermonuclear burning within the neutron star. groups from MIT, McGill University, the University of Minnesota, and the University of Amsterdam analyzed x-ray data from a NASA satellite. Researchers primarily focus on the crashing matter being pulled onto a neutron star by the stars intense gravitational pull, accretion. Accretion results in more matter, fuel, being added to the neutron star to a point where the star bursts with a volatile energy. This thermonuclear reaction can be detected and measured by x-ray satellites. The bigger the burst, the larger a spike found in the data. There are models that explain the frequency of the bursts relative to the amount of accretion. There should be more frequent bursts relative to more matter raining down on the neutron star, however, data has not reflected this side of the model. Alternatively, stars with low accretion should have large spikes in thermonuclear reactions separated by long measurable periods of time. This is the kind of data observed from Terzan 5.
While looking at Terzan 5, researchers noticed many small spikes relatively close together that resembled what a high-mass accretion rate neutron star would look like. At higher rates, the small spikes condense even more so and resemble an oscillating wave. A reason for this would be that the neutron star is gathering so much mass at one time that, somehow, the matter is heating up rapidly and fusing throughout the plasma evenly. One possible solution to this puzzle is the difference in the object being observed. Normally, neutron stars spin violently several hundred times a second, but the star viewed in Terzan 5 rotated at a mere 11 rotations per second. Perhaps the data for high accretion rates fitted so well was because the slow spin of the neutron star was negligible. This would mean a new model would have to be developed that incorporated the neutron star's spin. A justification for the dependance of spin in neutron star models would be that the tremendous spin of the neutron star creates friction between different layers of plasma and the neutron star which adds heat enabling fusion to occur.