Astronomers Uncover Secrets of Binary Pulsar Before It Disappears: Study

The system is called J1906 and located 25,000 light years away from Earth. It consists of a pulsar – a highly magnetized neutron star rapidly orbiting another dense object. As a pulsar rotates, it emits high-energy radiation. If this beam of radiation is pointed toward the Earth, these high-energy pulses can be detected using radio telescopes.

MOSCOW, January 10 (Sputnik) — Astrophysicists were able to determine some of the characteristics of a rare and mysterious occupant of our universe, a binary pulsar system, shortly before it disappeared from view because of a warp in space-time, according to a study published in the Astrophysical Journal.

An international team of researchers have closely monitored the pulsar for five years and were able to describe the masses of the two objects as well as the gravitation disturbance in the system. They say the space-time warp caused the disappearance of the pulsar system.

"Our result is important because weighing stars while they freely float through space is exceedingly difficult. That is a problem because such mass measurements are required for precisely understanding gravity, the force that is intimately linked to the behavior of space and time on all scales in our universe," Joeri van Leeuwen, an astrophysicist at The Netherlands Institute for Radio Astronomy ASTRON, and University of Amsterdam, The Netherlands, said in a press release.

The system is called J1906 and located 25,000 light years away from Earth. It consists of a pulsar – a highly magnetized neutron star rapidly orbiting another dense object (possibly another neutron star or a white dwarf) in just under four hours. As a pulsar rotates, it emits high-energy radiation. If this beam of radiation is pointed toward the Earth, these high-energy pulses can be detected using radio telescopes.

They call this system a relativistic binary pulsar, because the masses and densities of the two objects are so extreme so they can be best understood in the terms of Einstein’s relativity theory.

"These two stars each weigh more than the sun, but are still over 100 times closer together than the Earth is to the sun. The resulting extreme gravity causes many remarkable effects," Ingrid Stairs from the University of British Columbia, Canada, and a co-author of the findings published in The Astrophysical Journal, reportedly said.

One of these effects is known as geodetic precession of the spin axes of the pulsar. According to general relativity, if a neutron star moves through the highly curved space-time of a massive nearby companion star, its starts wobbling and its axis of rotation shifts.

The J1906 spin axis was wobbling so quickly that its beam of radio waves, previously seen every 144 milliseconds, no longer reaches Earth, the study finds.

The J1906 system was discovered in 2004 during a survey Dr. van Leeuwen and his colleagues were conducting at the Arecibo Observatory, in Puerto Rico.

"That was a real Eureka moment that night," he said as quoted by BBC. "It was strange, because that part of the sky's been surveyed lots of times — and then something really bright and new appears."

Currently, astronomers know of about 2,400 pulsars, and only 10 of those are double neutron star systems. Only a handful of such systems have had their masses measures, and J1906 is the youngest so far.

After its discovery, the team monitored J1906 with the world’s five largest radio telescopes and clocked one billion rotations of the pulsar.

The team kept track of the geodetic precession of J1906 and registered a change of 2.2 degrees in the orientation of the pulsar spin axes.

"The pulsar is now all but invisible to even the largest telescopes on Earth. This is the first time such a young pulsar has disappeared through precession. Fortunately this cosmic spinning top is expected to wobble back into view […] but it might take as long as 160 years," Dr van Leeuwen said.