Stellar object is discovered 15,000 light years from Earth – 07/25/2023 – Science

An international team of astronomers has discovered a new type of stellar object with characteristics that escape human understanding and which may be an ultralong-period magnetar — a rare type of neutron star with extremely powerful magnetic fields.

The discovery, published last week in the scientific journal Nature, was made by an international group of scientists led by astronomers from the International Center for Research in Radio Astronomy (Icrar) at Curtin University, Australia.

The researchers believe that the new stellar object could be an ultra-long-period magnetar, that is, a rare type of neutron star with ultra-strong magnetic fields capable of producing powerful bursts of energy, or a magnetic white dwarf star – an advanced stage in the life of a Sun-like star. None of these hypotheses, however, is able to fully explain the characteristics of the new object.

Ultra long period magnetar

Until recently known magnetars rotated in periods of a few seconds. The new object, however, emits radio waves every 21 minutes, making it the longest-period magnetar ever detected.

The discovery of the new object took place through the Murchison Widefield Array (MWA) radio telescope, located in the Aboriginal land of Wajarri Yamaji County, in the interior of Western Australia.

The magnetar, called GPM J1839-10, is 15,000 light-years from Earth in the constellation of Scutum.

“This extraordinary object challenges our understanding of neutron stars and magnetars, which are some of the most exotic and extreme objects in the Universe,” said Natasha Hurley-Walker, lead author of the study.

This is the second object of its kind detected so far, after the discovery of another in 2021 by a Curtin University student, reported by Nature in 2022. It was a radio source that repeated every 18 minutes and that shone for three months until it disappeared.

“We were baffled by this discovery and soon began looking for similar objects to see if it was an isolated occurrence or the tip of an iceberg,” explained Hurley.

A team of researchers searched the Milky Way using the MWA telescope and came across a signal that was repeated every 21 minutes and came from another part of space, more than 15 thousand light years away.

They found something unprecedented in GPM J1839-10: a magnetic field source that rotates producing pulses of up to five minutes in duration.

But, the most surprising discovery would come next. Using the object’s coordinates and characteristics, the team reviewed observation files from the world’s leading radio telescopes and found that GPM J1839-10 has been active for at least 33 years.

“Our object appeared in records from the Giant Metric Wave Radio Telescope (GMRT) in India and the Very Large Array in the United States, which had observations going back to 1988,” said Hurley.

Enigma to unravel

With data from the last 30 years, the researchers calculated that the source is just slowing down. Furthermore, after complex simulations carried out by scientists at the Institute of Space Sciences (ICE-CSIC) in Spain, theorists have serious difficulties trying to explain how it is possible to produce such a bright radio emission for so long.

“Assuming it’s a magnetar, it shouldn’t be possible that this object could produce radio waves. But we see them, and we’re not just talking about a little flicker of radio emission. Every 22 minutes it emits a five-minute pulse of radio wavelength energy, and it has been doing so for at least 33 years. Whatever mechanism produces it, it’s extraordinary.”

The discovery has important implications for our understanding of the physics of neutron stars and the behavior of magnetic fields at extreme contours, as well as raising new questions about the formation and evolution of magnetars and the origin of mysterious phenomena such as fast radio bursts.

But since the source is still active, astronomers around the world will continue to study it to better understand it and unlock its secrets.