A newly discovered neutron star is behaving so strangely that it could change our understanding of these super-dense objects left behind after the death of massive stars.
Astronomers have used the ASKAP radio telescope to discover a neutron star 13,000 light-years away that is so strange they say it should not exist. The star is likely a type of pulsar that has never been seen before. The study was published in the journal Nature Astronomy, New scientist reports.
When very massive stars reach the end of their lives and explode as supernova, a super-dense object called a neutron star is formed. Pulsars are neutron stars that rotate very quickly on their axis and emit radio waves from their magnetic poles as they rotate. Most pulsars rotate at more than one revolution per second, and astronomers receive a radio pulse at the same frequency.
In recent years, astronomers have discovered compact objects that emit radio waves much more slowly. This has confused scientists, because the radio emission is expected to stop when the rotation slows to more than one rotation per minute.
Such slowly rotating objects are known as long-lasting radio transients. Last year, astronomers discovered one with a rotation period of 54 minutes. Now astronomers have discovered a new object called ASKAP J1839-0756, which rotates at a record speed of one rotation every 6.45 hours.
Scientists initially thought the object was a white dwarf star, the remnant of a dead Sun-like star. But astronomers had never seen a lone white dwarf emitting radio waves. Calculations also showed that the new object was too large to be a white dwarf.
Then scientists decided that this object is a magnetar, that is, a neutron star with the strongest magnetic field in the universe. It is also a kind of pulsar. Astronomers have previously discovered a magnetar with a rotation period of 6.67 hours. But this magnetar only emits X-rays, not radio waves.
If it is indeed a lone magnetar, it would be the first star of its kind discovered to emit radio waves and thus rotate slowly on its axis, scientists say.
The study authors say the object completely changes known ideas about neutron stars. It’s one of the strangest objects in space and scientists thought it shouldn’t exist.
Astronomers also say the theory that pulsars stop emitting radio waves if they spin too slowly needs to be revised.
