A neutron star with one of the strongest magnetic fields in the universe has unexpectedly come back to life. Scientists have no clear explanation for this phenomenon.
Magnetars, a type of neutron star with enormous magnetic fields billions of times stronger than the Sun, are considered one of the most mysterious and frightening objects in the universe. These dense stars, the remnants of supernova explosions, continue to amaze astronomers by emitting incredibly high-energy X and gamma rays. In about 10,000 years, magnetars, whose magnetic fields weaken, turn into normal neutron stars and live on. But scientists have found that a dead neutron star with one of the strongest magnetic fields in the universe has unexpectedly come back to life.
An event that has never been detected before
The research team used the CSIRO Parkes radio telescope Murriyang to detect this exotic celestial phenomenon. The team discovered that XTE J1810-197, the closest known magnetar to Earth, located about 8,000 light-years away, was emitting strange radio signals and that this magnetar had returned from the dead.
First of all, even this discovery is a big deal. Most magnetars are known to emit light directed in a certain direction. However, the light of the magnetar that is the subject of the study is circularly polarized and spirals as it moves through space. This is not only unexpected but also unprecedented.
For those who don’t know, magnetars, like all neutron stars, are formed from the death of massive stars. These giant stars use nuclear fusion in their cores to generate the energy that keeps their gravity from collapsing inwards. But when the fuel for fusion (specifically, the conversion of hydrogen to helium) is depleted, meaning the energy source is gone, the star’s gravity takes over and causes it to collapse in on itself. This collapse triggers a supernova explosion, leaving behind an extremely dense object like a neutron star, including magnetars.
1 quadrillion times more powerful than the Sun
Magnetars and neutron stars are typically known to be between 10 and 20 kilometers in diameter. This means they are about 1,000 to 2,000 times smaller than the diameter of the Earth (about 12,742 km). But the density of magnetars is so great that a teaspoon of magnetar material brought to our planet would weigh about 100 million tons. When massive stars collapse and become magnatars and then neutron stars, they also start spinning at an incredible speed (700 times per second). At the same time, these dense objects can generate an incredible amount of magnetic field strength. The strength of this magnetic field can be a quadrillion (1 and then 15 zeros) times stronger than the Sun’s magnetic field.
Researchers are struggling to give a clear explanation
Although the research team’s observation was completely unexpected, the team has an idea why this magnetar is producing such unusual emissions. According to the researchers, there is a plasma with very high temperatures above the magnetar’s magnetic pole. This plasma is thought to act like a polarizing filter, but how this happens is a big question mark. The researchers hope that ongoing observations of Murriyang and XTE J1810-197 will help provide information on a range of extreme, powerful and unusual phenomena related to the magnetar, such as plasma dynamics, X-rays, gamma-ray bursts and potentially fast radio bursts.
