A team of astronomers has solved the mystery of a repeating radio signal that was first detected over a decade ago. The signal, which repeats every 2 hours, was initially thought to be caused by a neutron star but the new research reveals that it is actually coming from a binary system containing a dead star and a red dwarf stellar companion.
According to team leader Iris de Ruiter from the University of Sydney in Australia, the discovery was made using archival data collected by the Low Frequency Array (LOFAR). The pulse first appeared in LOFAR data in 2015 and after finding its first instance, de Ruiter found six more pulses from the same source. The flashes of radio waves can last anywhere from several seconds to a few minutes and despite their differences in duration, they repeat regularly.
The team’s research indicates that the cause of this repeating radio signal is the magnetic fields of the white dwarf and its red dwarf stellar companion slamming together in this tight binary, designated ILTJ1101. This discovery puts an entirely new spin on our understanding of long-period radio bursts and neutron stars.
“We know at least some long-period radio transients come from binaries,” said team member Charles Kilpatrick. “This motivates radio astronomers to localize new classes of sources that might arise from neutron star or magnetar binaries.”
The binary system consists of a dead star, known as a white dwarf, and a red dwarf stellar companion. The two stars are pulsing in unison, with the white dwarf moving back and forth rapidly due to the gravitational pull of its companion. This movement reveals the mass of the very faint companion.
This discovery is significant because it confirms the leading hypothesis for the origin of long-period radio transients. Astronomers plan to study the high-energy ultraviolet emissions of ILTJ1101, which could reveal more details about this system and potentially shed light on other similar systems.
The research was published in the journal Nature Astronomy on Wednesday. The team’s efforts demonstrate that scientists can work together across different disciplines to solve complex puzzles like this one, with Dr. de Ruiter saying “It was especially cool to add new pieces to the puzzle.”
Source: https://www.space.com/the-universe/astronomers-crack-the-case-of-a-mysterious-deep-space-radio-signal-that-repeats-every-2-hours