What happens when a neutron star rotating hundreds of times per minute flies through the clutches of a huge star 15 times the mass of the Sun? In spring 2018, astronomers are due to find out in a hotly anticipated “high-energy firework” event.
That’s when the pulsar J2032+4127, or just J2032 for short, will plow through the outer atmosphere of its massive companion star, MT91 213, at up to 300 kilometers (190 miles) per second. NASA is planning to train a host of telescopes on the binary system located 5,000 light-years from Earth to watch the event unfold.
J2032, the remnant of a star that went supernova, is about 20 kilometers (12 miles) across, has about twice the Sun’s mass and completes a rotation seven times a second. MT91 213, meanwhile, is classified as a Be star – a large and hot star that loses large amounts of material due to its own rapid rotation of 200 kilometers (120 miles) per second – and is 10,000 times brighter than the Sun.
The discovery of the upcoming event, published in the Monthly Notices of the Royal Astronomical Society, was made by an international team that included Andrew Lyne from the University of Manchester, who told IFLScience that it would be comparable to a meteor passing through Earth’s atmosphere but “on a vastly different scale.”
The two stars have the longest orbit of any binary system containing a radio pulsar, estimated at about 25 years. While this will not be the first event of this kind to be observed, it has a bigger orbit and involves much more massive stars than anything seen before.
“We do not know for sure what to expect,” said Lyne. “Events like this are extremely rare and we have witnessed only two other systems with encounters like this, but with smaller orbits and with less massive stars, so there is not much to go on observationally.”
The scientists aren’t sure exactly how close the stars will get, as the pulsar has only been tracked for five years of its orbit, but it's thought that it will at least pass through the large disk of material that surrounds its companion. This will enable the gravity and magnetic field of the larger star to be measured.
This graphic shows the path that the pulsar is expected to take around its companion star. NASA's Goddard Space Flight Center.
The pulsar, initially discovered by NASA’s Fermi Gamma-ray Space Telescope, was studied further by follow-up observations using the Lovell Radio Telescope at Jodrell Bank in Manchester. When the dramatic event takes place in 2018, though, a global suite of telescopes will be watching closely to provide astronomers with a front row seat.
A quarter of a century later, the pulsar will be dragged back for another close encounter, when a whole new array of telescopes will likely tune in for another instalment.