There are neutron stars that behave strangely. At one time this star resembled a pulsar. But, at different times the star looks like a magnetar?

Pulsar or magnetar?

Pulsars are neutron stars which rotate rapidly, which is the rest which is left behind from death a massive star.

Magnetars are celestial bodies that have the strongest magnetic fields in the universe. It is formed when massive stars burst.

The star in the spotlight is named PSR J1119-6127 aka J1119. Quite mysterious because its behavior shows the nature of two different objects, namely pulsars and magnetars. Although it seems different, the presence of J1119 certainly brings interesting stories as well as a challenge for astronomers to be able to understand its evolution and discover why its behavior is like that.

For astronomers, pulsar radio and magnetar are two different types of neutron stars. From its characteristics, the radio pulsar is the rest of the starburst that emits radio waves with regular pulsations as a result of its rapid rotation. Meanwhile, magnetars actually have more dangerous behavior. Magnetars give off X-rays and high-energy gamma rays and ultra-strong magnetic fields.

From the observation, J1119 does not have a regular pulse. At certain times, the pulse rhythm changes and releases bursts. But, when J1119 throbs, this star can keep the pulse rhythm. Strange? Let's take a quick look at J1119.

The mysterious object J1119 was discovered in 2000 as a radio pulsar. All is fine until 2016 when NASA's Fermi and Swift telescopes saw two X-ray bursts and 10 low-energy bursts coming from the same object.

This incident certainly triggered the question of what was going on. Why this radio pulsar suddenly rebelled and started acting like a magnetar, the neutron star who had a very strong magnetic field. Or is this one phase in a neutron star to go through?

J1119 seems to be able to divide the time to be in two different neutron star conditions. There are times when he behaves as a pulsar, with a regular pulse in the supernovae core, and at other times becomes a magnetar, whose emissions are controlled by the decay of the magnetic field and not the star rotation.

X-ray bursts on J1119 are thought to occur because the star's magnetic field changes as the star rotates. Large pressures during magnetic field changes are thought to be the cause of the outer crust of the cracked neutron star resulting in a rotational change. In further observations made, it is also known that the radiation intensity of J1119 radio waves strengthens and weakens very sharply. And in 10 days, J1119 starts to behave like a normal radio pulsar back.

The evidence obtained is likely to favor a single phase of evolution that neutron stars are passing through. Transition phase of radio pulsars and magnetars. This phase has never been seen before. Of the approximately 2500 pulsars in the Milky Way, J1119 is the first to show such behavior.

Could be, this phase is a missing link that can connect pulsars and magnetars. But there is another question which then appears. Which one comes first, pulsars or magnetars?

There is a debate. Some scientists argue that neutron stars like J1119 start the magnetar phase first. Slowly the X-ray bursts and gamma rays decrease and eventually stop and then enter the pulsar phase. But there is another theory. Neutron stars such as J1119 start the pulsar radio phase first and over time the magnetic field emerges from the rest of the supernova and in the end, there is a burst like a magnetar.

The exact answer does not yet exist, and it is the homework of astronomers to make further observations on similar objects.