Clash of neutron stars: a mysterious catastrophe
In August of this year, astronomers watched as two neutron stars merged with each other, producing gravitational waves and a huge explosion in strength. Then scientists did not fully understand what was formed as a result: one colossal neutron star, black hole, or something else.
Yun-Wei Yu at Central China Normal University and Zi-Gao Dai at Nanjing University in China simulated this explosion (the so-called Kilon bombing ), which in reality can last from several weeks to several months. According to their calculations, only one, but very large neutron star should remain at the site of the collision.
The collision of neutron stars: how does this happen
There are three main theories of what can happen in such a collision. In the first case, a black hole is formed; in the second, it turns out a neutron star that lives only a few milliseconds, after which it turns into either a black hole or the third option - a stable neutron star. If in this case everything went according to the third scenario, then astronomers were lucky to observe the largest neutron star ever discovered.
The gravitational waves that scientists observed with LIGO will not be able to clarify the situation. However, Kilonova comes to the aid of scientists here.
Since neutron stars initially rotate in a spiral, they can accelerate to about 1/3 of the speed of light, explains Edo Berger of Harvard University. When two such stars collide and become one, the object retains this momentum and, as a result, rotates incredibly fast. In the process of this, a huge star radiates energy, which either additionally accelerates the process, or, conversely, slows it down. If a neutron star slows down to a threshold limit, it will inevitably start a spontaneous process of turning into a black hole. The exact mass at which the collapse of the celestial body occurs is still unknown - it is only clear that the star must be colossal.
Earth's point of view
Thus, astronomers can only watch the kilo. An increase in the level of radiated energy will mean that two stars have successfully merged into one. “For a neutron star, a Kilonova represents radiation of energy in different directions, while for a black hole it’s just a powerful impulse in one direction, a kind of“ jet stream that will cause a noticeable gamma-ray burst, ”says Berger.
Now the opinions of scientists differ. Yu and Dai are confident that their mathematical model is correct and that a huge neutron star has formed as a result. Berger, in turn, points to a powerful gamma pulse and is confident that the collision led to the appearance of a new black hole. In addition, he notes that the surge of energy in the model of Chinese scientists overshadows the explosion itself, which astronomers observed using telescopes.
In the next few weeks, the situation should be resolved. If earlier all theories were based on hypotheses, now researchers have only to decipher the evidence and finally find out what happened as a result of such a phenomenal disaster.