Dead star helps scientists solve secret of mysterious signals from space

Astronomers' observations

For some time, astronomers have observed powerful disturbances in the magnetar (a neutron star with an extremely strong magnetic field) near the heart of the Milky Way. These are sudden changes in the star's rotation that can occur as a result of sudden structural changes.

It is known that neutron stars (also called dead stars) arise after the death of massive ordinary stars. They are a very dense core of a dead star, consisting of neutrons.

This dead star has a diameter of about 20 km, but its mass may be twice that of the Sun. The researchers found that the glitches may have accelerated her speed significantly.

At the same time, the phenomenon that slows down the neutron star after such failures can help to unravel the mystery - what happens inside the magnetar and how these strange bodies trigger the so-called fast radio bursts, or FRBs (from English - 'fast radio bursts').

What is known about fast radio bursts

Fast radio bursts (FRBs) are mysterious and fleeting pulses of light (radio bursts) that can be so bright that they briefly outshine an entire galaxy. At the same time, they "carry" a huge amount of energy.

Scientists know that such pulses lasting a few seconds exist, but no one has yet been able to determine exactly why they occur and what their nature is.

The difficulty lies in the fact that most fast radio bursts are formed far outside our galaxy, so their exact location can be determined, but why they occur is difficult to understand.

FRB-emitting magnetar (image: ESA)

Results of research

The studied FRB originated in the Milky Way at a distance of 30 thousand light years from Earth in 2020. The source of the radio burst was the magnetar SGR 1935+2154, which was also a pulsar (a type of neutron star that is a cosmic source of electromagnetic radiation).

Scientists hypothesized that this star was experiencing flares similar to similar energy releases on the Sun, and tried to understand how exactly the magnetar could release such a huge amount of energy in a very short period of time.

It is specified that the authors of the study used:

• the NICER instrument on board the International Space Station

• the NuSTAR space telescope

The scientists found that the magnetar normally makes three complete rotations per second, but the first failure caused an increase in rotation speed, and the second caused another increase in speed (100 times more than the first).

In the interval between the occurrence of failures, scientists observed a significant decrease in the speed of rotation of the neutron star - that's when the magnetar released the FRB.

According to the results of the research, it can be assumed that there is a connection between fast radio bursts and the rotation speed of the magnetar.

The authors of the study assume that the accumulated magnetic energy of the neutron star was thrown out due to the fact that the necessary conditions for its appearance in the form of a change in the rotation of the magnetar appeared.

Earlier, we reported on how scientists are going to inhabit the Moon in the next 50 years.