“So we know that the pulsations are coming from a region close to the white dwarf, or possibly even from the white dwarf itself,” said Dr Sam McSweeney, commissioning scientist with the Square Kilometre Array Observatory.
Astronomers have traced a mysterious radio signal flashing every eight minutes back to a binary system, according to findings published on Thursday (Nov. 12) in the journal Nature Astronomy. The system, designated GPM J071507−114153, contains a dead star known as a white dwarf and a companion star similar to our sun.
Classified as long-period transients (LPTs), GPM J071507−114153 is part of a group of objects recognized for emitting radio waves that activate and deactivate every few minutes or hours. Ever since the research group uncovered the initial example in 2021, roughly a dozen LPTs have been spotted.
Prior LPT systems have been found to house both a white dwarf and a companion star, yet uncertainty remained regarding which of the two stellar bodies actually produced the radio pulses.
The research team spotted the system using the Murchison Widefield Array to scan the Milky Way visible from Australia. They then used the MeerKAT radio telescope in South Africa to determine its precise position. The system was confirmed using the W.M. Keck Observatory on Maunakea in Hawaii.
According to Natasha Hurley-Walker from Curtin University’s International Centre for Radio Astronomy Research (ICRAR) in Australia, the stellar wind from the companion star continuously supplies charged particles to the white dwarf, which possesses a powerful magnetic field. The white dwarf in the system spins once every eight minutes.
“It’s amazing that by using radio wavelengths we can detect the storms on a star over 5,000 light-years away,” Hurley-Walker said.
Acting as precursors to the world’s largest and most sensitive radio telescope project, the Square Kilometre Array (SKA), both the MWA and MeerKAT share this role. McSweeney said that future discoveries will provide a highly detailed view of these signals once the SKA telescopes are completely built.
Earlier coverage: Chandra X-Ray Observatory Finds Hidden Companion to Massive Star, Study Finds