Bizarre Star Unlike Any Other Defies Scientific Explanation

May 28, 2025

Jeremy Gray

A colorful space scene showing a dense star field, glowing clouds of gas in orange, yellow, blue and green hues, and a prominent red arc, with a small white circle highlighting a spot on the right side. — A wide field image of ASKAP J1832 in X-ray, radio, and infrared light. Credit: X-ray: NASA/CXC/ICRAR, Curtin Univ./Z. Wang et al.; Infrared: NASA/JPL/CalTech/IPAC; Radio: SARAO/MeerKAT; Image processing: NASA/CXC/SAO/N. Wolk

A global team of astronomers using NASA’s Chandra X-ray Observatory and the Square Kilometer Array Pathfinder (ASKAP) radio telescope discovered a bizarre star that acts unlike any star seen before.

By combining data from Chandra, which is in orbit above the Earth’s atmosphere, and ASKAP in Australia, scientists have discovered a unique object, ASKAP J1832-0911. Located approximately 15,000 light-years from Earth, this star belongs to a very small, new class of objects called “long period radio transients.” Discovered in 2022, these types of objects emit regular radio waves that vary in intensity over periods of tens of minutes, which is, as the Chandra team explains, thousands of times of longer than repeated variations of similar emissions observed in pulsars. Pulsars are rapidly spinning neutron stars, and their variations occur on a sub-second timescale.

A glowing red astronomical object labeled “ASKAP J1832–0911” is circled at the center, surrounded by diffuse red and blue spots on a dark background, resembling a cosmic observation image. — A close-up image of ASKAP J1832 in X-ray and radio light. Credit: X-ray: NASA/CXC/ICRAR, Curtin Univ./Z. Wang et al.; Radio: SARAO/MeerKAT; Image processing: NASA/CXC/SAO/N. Wolk

ASKAP J1832 is much different. It cycles radio wave intensity every 44 minutes. However, what makes it unique among long period radio transients is that not only does the star emit regular cycles of radio waves, it is also emitting an X-ray signal — something never observed before.

“Astronomers have looked at countless stars with all kinds of telescopes and we’ve never seen one that acts this way,” says Dr. Ziteng Wang from the Curtin University node at the International Centre for Radio Astronomy Research (ICRAR) in Australia. Dr. Wang is the lead author on the associated research published today in Nature.

“It’s thrilling to see a new type of behavior for stars,” Dr. Wang continues.

The exciting discover goes even further. ASKAP J1832’s radio and X-ray signals also dipped dramatically over six months. Astronomers have never seen anything like that in the Milky Way galaxy, either.

A blurry, abstract image featuring various shades of red with some brighter and darker areas, suggesting swirling or cloudy shapes on a black background. — ASKAP J1832 and its surrounding area as seen in radio waves

Now scientists are racing to determine if ASKAP J1832’s bizarre behavior is reflective of long period radio transients — a relatively very new field of study — or if its oddities are an outlier. Little is yet known about the origin of such objects.

“We looked at several different possibilities involving neutron stars and white dwarfs, either in isolation or with companion stars,” says study 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.”

A two-panel graph shows radio brightness (top, ASKAP) and X-ray brightness (bottom, Chandra) versus phase. Radio has sharp peaks at phases 0 and 1. X-ray has broader peaks at the same phases, with error bars. — ‘A figure showing variations in the radio and X-ray brightness of ASKAP J1832. The X-axis shows the phase of the repeated variations, a quantity that is proportional to time. The two plots were generated by taking the full light curves — the variations in brightness as a function of time — and cutting them up into 44 minute-long segments. These segments are then mathematically laid on top of each other and added together to give average signals in X-rays or radio waves at different portions, or phases, of the 44 minute-long cycle. A phase of 0.0 corresponds to the beginning of this average signal and a phase of 1.0 corresponds to the end of the average signal, 44 minutes later. The signal repeats between phases of 1.0 and 2.0. The full light curve covers about 10 cycles of the 44 minute long signal for radio and about 8 for X-rays. The red lines in the X-ray plot show the uncertainties in the X-ray signals. Creating plots like this enables a good view of the average variations in light with time.

Some explanations make sense in certain ways but fall short in others. For example, some of ASKAP J1832’s behavior is reminiscent of that of a neutron star with a powerful magnetic field, known as a magnetar. However, its brightness and variable radio emission don’t align with that theory.

On the cosmic canvas, ASKAP J1832 appears to live inside a supernova remnant or the remains of an exploded star. However, the object’s home seems unrelated to its properties, leading scientists to think that the odd star probably does not contain a neutron star.

However, an isolated white dwarf does not justify the available data.

“But a white dwarf star with a companion star might,” the Chandra X-ray Observatory team explains. However, if that is true, it would require the existence of the most powerful magnetic field ever observed for a white dwarf in the Milky Way galaxy.

“We will continue to hunt for clues about what is happening with this object, and we’ll look for similar objects,” says co-author Dr. Tong Bao of the Italian National Institute for Astrophysics (INAF) — Osservatorio Astronomico di Brera in Italy. “Finding a mystery like this isn’t frustrating — it’s what makes science exciting!”

Image credits: Credit: X-ray: NASA/CXC/ICRAR, Curtin Univ., Z. Wang et al.; Infrared: NASA/JPL/CalTech/IPAC; Radio: SARAO/MeerKAT; Image processing: NASA/CXC/SAO/N. Wolk. The associated research paper, “Detection of X-ray Emission from a Bright Long-Period Radio Transient,” was published today in Nature. The lead author is Ziteng Wang.