Image Credit: NASA's Goddard Space Flight Center 
On Oct. 5, 2020, the rapidly rotating corpse of a long-dead star about 30,000 light years from Earth changed speeds. In a cosmic instant, its spinning slowed. And a few days later, it abruptly started emitting radio waves.
Thanks to timely measurements from specialized orbiting telescopes, Rice University astrophysicist Matthew Baring and colleagues were able to test a new theory about a possible cause for the rare slowdown, or “anti-glitch,” of SGR 1935+2154, a highly magnetic type of neutron star known as a magnetar.
In a study published this month in Nature Astronomy, Baring and co-authors used X-ray data from the European Space Agency’s X-ray Multi-Mirror Mission (XMM-Newton) and NASA’s Neutron Star Interior Composition Explorer (NICER) to analyze the magnetar’s rotation. They showed the sudden slowdown could have been caused by a volcano-like rupture on the surface of the star that spewed a “wind” of massive particles into space. The research identified how such a wind could alter the star’s magnetic fields, seeding conditions that would be likely to switch on the radio emissions that were subsequently measured by China’s Five-hundred-meter Aperture Spherical Telescope (FAST).