Astronomers have likely solved the mystery behind some of the most powerful and puzzling signals from space. Known as long-period radio transients, these signals emit regular blasts of radio waves and X-rays on a repeating 1.4-hour cycle, and have been detected from only a few remote regions of our galaxy.
Researchers now believe they have pinpointed the source: a white dwarf star pulling material from a larger, less dense companion star. As the material spirals inward, it generates the intense blasts. The findings are published in a new paper in the journal Nature Astronomy.
“For the first time we have pinpointed the origin of these signals, confirming the source to be a ‘cataclysmic variable’, or an accreting white dwarf star,” said Kovi Rose, a PhD student at the University of Sydney who led the discovery. “Long-period radio transients have puzzled astronomers for years. We’ve only found about a dozen, and their origins have been unclear. Now, we’ve been able to show that the source for one of these transients comes from a white dwarf actively pulling material from a companion star.”
The system, designated ASKAP J1745−5051, consists of two stars orbiting extremely closely. The interaction heats the accreted material, producing X-rays, while the stars’ magnetic fields generate the regular radio bursts. Earlier theories suggested the transients came from slow-spinning neutron stars called pulsars, but such slow rotations could not explain the signals.
Scientists hope this breakthrough will help decode other similar signals. The study provides the first confirmed origin for a long-period radio transient, opening a new avenue for understanding these enigmatic cosmic phenomena.
