Astronomers have traced a set of unusual radio pulses to a close pair of stars about 5,000 light-years away: a white dwarf and a sun-like companion, Space.com reports. The system is designated GPM J071507−114153. The white dwarf spins once every eight minutes and sends out the pulses.
Objects like this are called long-period transients, radio sources that switch on and off over minutes or hours. Only about a dozen have been found since the first one in 2021, and in several white-dwarf binaries it wasn’t clear which star was actually producing the signal. This time the pulses were clean enough to show the white dwarf moving in its orbit, which means the radio source is close to the white dwarf, or possibly the white dwarf itself. “This is the first time the pulses are clear enough to see the white dwarf moving in its orbit around its companion,” said team leader Sam McSweeney of the Square Kilometre Array Observatory.
As a bonus, the same data picked up flares on the sun-like star, including what looks like the white dwarf passing behind a strong magnetic loop of plasma, a stellar prominence, on the companion. Natasha Hurley-Walker of the International Centre for Radio Astronomy Research put it simply: it’s amazing to detect storms on a star more than 5,000 light-years away, just by listening in radio.
My take
I love a mystery that gets a name and a clock rate. An eight-minute white dwarf, dragging a sun-like neighbor along, lighting up in radio and showing off stellar weather as a bonus, is a delightful kind of odd couple. The universe keeps being stranger than the first draft of the catalog.
God Bless, and May the Source Be with You!
