Radio pulses located near white dwarf orbiting a Sun-like star
Researchers say this is the first detection of such signals from a system pairing a white dwarf with a star in the same category as the Sun.
Astronomers have located the likely origin of unusual radio pulses near a white dwarf in a two-star system more than 5,000 light-years from Earth. The team at Curtin University's branch of the International Centre for Radio Astronomy Research (ICRAR) said the signals could also come from the white dwarf itself.
Named GPM J071507−114153, the system pairs a white dwarf rotating every eight minutes with a G-type star resembling the Sun. Researchers said earlier detections of similar pulses involved white dwarfs paired with red dwarfs, which are cooler and smaller.
Lead author Dr. Sam McSweeney said the radio measurements allowed researchers to track the white dwarf's movement around its companion and narrow down where the pulses originate. The analysis used radio observations totaling more than 100 hours and computing facilities at the Pawsey Supercomputing Research Centre.
The system belongs to a group known as long-period transients, which emit intermittent radio signals over intervals of minutes to hours. Their origins are still poorly understood. Co-author Associate Professor Natasha Hurley-Walker said the measurements also showed stellar flares and evidence of a strongly magnetic region near the companion, most likely a large plasma loop.
Detection began with an MWA survey in Western Australia. MeerKAT in South Africa subsequently pinpointed the system's position, and optical measurements from the W.M. Keck Observatory linked the radio source to a G-type star. Nature Astronomy published the findings.
