Scientists have discovered a unique star 15,000 light-years from the solar system that appears to pulse every 44.2 minutes.
Separate data from NASA’s orbital Chandra X-ray Observatory and the Square Kilometer Array radio telescope in Western Australia found the star — named ASKAP J1832 — in 2024, according to the paper published today in Nature.
Radio And X-Ray
The star is what astronomers call a long-period radio transient, which they have detected since 2022. However, this is the first time such an object has also been observed to emit X-rays. X-ray emission is high-energy electromagnetic radiation, which Earth’s atmosphere blocks. Both the radio and X-ray pulses are tightly aligned in phase, so they must be coming from the same object.
“Astronomers have looked at countless stars with all kinds of telescopes, and we’ve never seen one that acts this way,” said Dr Ziteng Wang, first author of the paper, from the Curtin University node at the International Centre for Radio Astronomy Research in Australia. “It’s thrilling to see a new type of behavior for stars.”
Longest Ever Found
Long-period radio transients vary in the intensity of their radio waves in a regular way over tens of minutes, but this is by far the longest ever found. The discovery suggests that these strange objects can be significantly more energetic than previously believed. First observed in February 2024, ASKAP J1832 dropped in intensity in both radio waves and X-rays over the following six months, becoming 1,000 times fainter by August 2024.
What exactly ASKAP J1832 is remains a mystery. The transient likely harbors a compact object, possibly an ultra-magnetized white dwarf (the dense core left by a star that has exhausted its fuel) or an old magnetar (the extremely dense remnant of a star that has exploded as a supernova). However, scientists cannot fully explain either origin. “We looked at several different possibilities involving neutron stars and white dwarfs, either in isolation or with companion stars,” said co-author Dr Nanda Rea of the Institute of Space Sciences in Barcelona, Spain. “So far, nothing exactly matches up, but some ideas work better than others.”
White Dwarf Vs. Magnetar
ASKAP J1832 appears to be within a supernova remnant, but the researchers think that’s a coincidence, so it may not be a magnetar. It may be a white dwarf star with a companion star, but only if it had the strongest magnetic field ever known for a white dwarf.
“We will continue to hunt for clues about what is happening with this object, and we’ll look for similar objects,” said co-author Dr Tong Bao of the Italian National Institute for Astrophysics – Osservatorio Astronomico di Brera in Italy.
Wishing you clear skies and wide eyes.
