Astronomers have deciphered the strange behavior of the pulsar J1023+0038. This pulsar, which rapidly transitions between two brightness states, emits material in sudden bursts that cause these transitions. Thanks to this breakthrough, which included extensive observations and analyses, we better understand the dynamics of pulsars
Astronomers have deciphered the strange behavior of the pulsar J1023+0038. This pulsar, which rapidly transitions between two brightness states, emits material in sudden bursts that cause these transitions. Thanks to this breakthrough, which included extensive observations and analyses, we better understand the dynamics of pulsars.
In a major astronomical study involving 12 telescopes on the ground and in space, including three facilities of the European Southern Observatory (ESO), astronomers discovered the strange behavior of a pulsar, a dead star that spins very fast. This mysterious object switches between two brightness states almost constantly, something that has been a mystery until now. But astronomers have now discovered that sudden ejections of material from the pulsar over very short periods of time are responsible for the strange transitions.
"We have seen unusual cosmic events in which huge amounts of material, similar to cosmic shells, are launched into space within a very short period of tens of seconds from a small, dense celestial object that is spinning at unbelievably high speeds," says Maria Cristina Baglio, lead author of the article recently published in the journal Astronomy & Astrophysics.
A pulsar is a magnetically dead star that rotates rapidly and emits a beam of AM radiation into space. As it rotates, this beam scans the cosmos—much like a lighthouse beam scans its surroundings—and astronomers detect it when it cuts the line of sight to Earth. This makes the star appear from Earth as a pulse of brightness.
PSR J1023+0038, or J1023 for short, is a special type of pulsar with strange behavior. It is about 4500 light-years from Earth in the Sextant group, closely orbiting another star. Over the last decade, the pulsar has been actively attracting material from this companion, which accumulates in the disk around the pulsar and slowly falls into it.
Since this process of accreting matter began, the scanning beam effectively disappeared and the pulsar began to transition continuously between the two states. In the "high" mode, the pulsar emits X-rays, UV and bright visible light, and in the "low" mode, it is dimmer at these frequencies and emits more radio waves. The pulsar can stay in each mode for a few seconds or minutes, then switch to the other mode in just a few seconds. This transition is so far a puzzle for astronomers.
"We discovered that the transition between the states results from a complex interaction between the wind of the pulsar, a flow of high-energy particles moving away from the pulsar, and matter flowing into the pulsar," says Coti Zaletti from the Italian National Institute of Astrophysics.
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