(ORDO NEWS) — A couple of years ago, a distant magnetar suddenly abruptly slowed down its rotation and began to emit radio waves.
American astrophysicists explained this by the sudden appearance of a crack through which a powerful stream of particles began to beat from the surface of the star.
Incredibly dense and compact neutron stars can have extremely powerful magnetic fields. Such magnetars rotate rapidly, emitting radiation in the X-ray and sometimes other wavelengths.
Observing them in x-rays, scientists determine the speed of rotation, and, as a rule, it slowly decreases – on a scale of thousands of years.
Recently, however, the magnetar SGR 1935+2154, located 30,000 light-years away, has shown itself in a completely unexpected way.
In October 2020, astronomers noticed that SGR 1935+2154 slowed down dramatically, and a few days later turned into a source of fast repetitive radio bursts.
And recently, the team of Rice University professor Matthew Baring (Matthew Baring) studied the observational data for this magnetar and offered an explanation for such unusual behavior.
It is worth saying that occasionally magnetars can experience a sharp jump in rotational speed.
According to existing ideas, this is due to the fact that the outer layers of the star are gradually slowing down, while the core maintains a more stable rotation rate.
As a result, stress accumulates at the interface between them, which can be “discharged” by a sudden transfer of momentum from the core to the surface.
In contrast to this picture, SGR 1935+2154 showed not a sharp acceleration, but the same deceleration. Such events are found much less frequently. According to Professor Baring, only three have been registered so far.
That is why the behavior of the magnetar attracted such close attention of scientists who observed it with the help of both X-ray (XMM-Newton, NICER) and radio telescopes (FAST).
Baring and his colleagues decided that it was no coincidence that the sharp slowdown and the appearance of the radio signal almost coincided in time.
They attributed this to a rupture on the surface of SGR 1935+2154 and a stream of massive particles that escaped from the resulting crack.
The impulse of this “stellar wind” could affect the rotation of the magnetar itself, as well as change the geometry of the magnetic field surrounding it.
In turn, changes in the magnetic field manifested themselves in the form of bursts in the radio range.
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