Scientists have found a celestial body, which turned out to be the most powerful known magnet in the entire universe. We are talking about a neutron star located almost 20 thousand light years from Earth.
The achievement is described in a scientific article published in the Astrophysical Journal Letters.
We have already talked more than once about magnetars – special neutron stars that are rightfully considered the strongest magnets in the Universe.
Now scientists have measured the magnetic field of the GRO J1008-57 magnetar and found that it is about one billion tesla. This is the strongest magnetic field ever measured, according to a press release from the study. And of course, the record set by physicists on Earth cannot be compared with it: 2800 Tesla.
Measuring the magnetic field of a distant celestial body is a difficult task. Astronomers cannot reach it with a magnetometer. They have to be content with radiation reaching Earth’s telescopes.
GRO J1008-57 is an X-ray pulsar. It forms a close pair with an ordinary star and “steals” matter from it with the help of its powerful gravity. This matter falling on the neutron star is highly heated and radiates in the X-ray range.
In 2017, the Chinese orbiting X-ray telescope Insight-HXMT detected a spectral line in GRO J1008-57 radiation known as the cyclotron resonance scattering line. Without bothering the reader with details, let us say that the magnetic field strength can be calculated from the energy of the quanta of this line.
The researchers emphasize that the spectral line was detected with colossal reliability: more than 20 sigma. Meanwhile, the gold standard for reliability is just five sigma. Thus, it is completely impossible that the observed line is just a false alarm, a random combination of noise.
The measured quantum energy of 90 keV corresponded to a huge magnetic field of a billion Tesla. Let us emphasize that these figures fit well into existing ideas. According to some estimates, the strongest magnetars have fields of up to one hundred billion Tesla. But these figures are based on not very reliable additional assumptions about the relationship between the pulsar’s magnetic field and the speed of its rotation around its axis. Measurement from Insight-HXMT telescope data is made in a more reliable way.
Now GRO J1008-57 can become the object of close attention of scientists. After all, such colossal magnetic fields, as theorists believe, change the properties of matter and even the vacuum itself. Nature itself has arranged a laboratory unsurpassed in its capabilities for physicists.