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| A wide field image of ASKAP J1832 in X-ray, radio, and infrared light. |
In a remarkable astronomical discovery, scientists have identified a star behaving in ways never before observed, potentially revealing a new class of celestial objects. The source, named ASKAP J1832−0911 (or ASKAP J1832 for short), challenges current understanding of stellar phenomena and could rewrite theories about the life cycles of stars.
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| A close-up image of ASKAP J1832 in X-ray and radio light. |
A team of astronomers used data from NASA’s Chandra X-ray Observatory and the ASKAP (Australian Square Kilometre Array Pathfinder) radio telescope, located on Wajarri Yamaji Country in Western Australia, to study this enigmatic source.
ASKAP J1832 is part of a rare category known as “long period radio transients,” first discovered in 2022. These objects emit radio waves in a predictable cycle that unfolds over tens of minutes—far slower than the milliseconds-scale pulses of typical neutron stars, known as pulsars. ASKAP J1832 emits a radio signal every 44 minutes, making it one of the slowest cyclic emitters ever recorded.
What makes ASKAP J1832 even more extraordinary is the discovery of matching X-ray pulses occurring every 44 minutes—a first for any known long period radio transient. This dual-behavior was identified using Chandra’s powerful X-ray instruments, confirming the object’s unique multi-wavelength variability.
In addition to its rhythmic 44-minute cycles, ASKAP J1832’s emissions have dramatically decreased in both radio and X-rays over a span of just six months, baffling astronomers further.
Not Your Average Pulsar or Magnetar.
While pulsars and magnetars (neutron stars with extremely strong magnetic fields) are known for their regular emissions, ASKAP J1832 doesn’t neatly fit either profile. Its signal strengths, variation timescale, and long-term fading are inconsistent with typical neutron stars.
Some features could be explained by an older magnetar, over 500,000 years old, but its powerful and irregular radio emissions make this explanation problematic. Alternatively, the team explored whether ASKAP J1832 might be a white dwarf—a dense stellar remnant left after a star like our Sun dies—perhaps with a companion star. If so, the white dwarf would need to possess the strongest magnetic field ever detected in our galaxy.
A Cosmic Coincidence?
On the sky, ASKAP J1832 appears to reside within a supernova remnant, the cloud of gas and dust left behind by an exploded star. Such remnants often house neutron stars, but researchers believe this alignment is likely a coincidence. No clear physical connection has been established between the two.
A Tale of Two Teams.
This discovery, led by Dr. Ziteng Wang of Curtin University, is described in a newly published paper in Nature. Intriguingly, a second team using the DAocheng Radio Telescope independently identified ASKAP J1832 and submitted their own findings to the arXiv preprint server on the same day. However, their study does not include the crucial X-ray observations made by Chandra.
Stunning Images Highlight a Galactic Mystery.
Two composite images released with the study offer a visual context for ASKAP J1832’s location and peculiar nature:
The primary image combines data from Chandra (X-ray, blue), LOFAR (radio, red), and NASA’s Spitzer Space Telescope (infrared, green and orange). The object appears as a tiny purple speck near the center of a red supernova remnant.
A close-up view strips away the infrared background, revealing the object as a bright white dot with a glowing pink rim—its unusual presence stark against the darkness of space.
These findings raise more questions than answers, but they also open a new window into the dynamic and mysterious life of stars in our galaxy.