Mysterious Hourly Signal from Space Puzzles Scientists

janimonow

June 8

Radio Star

A repeating radio signal from deep space, emitting every 54 minutes, has left scientists scratching their heads. Detailed in a study published in Nature Astronomy, this signal is suspected to originate from a neutron star known as a pulsar. However, the object's slow rotation rate is baffling researchers.

Their working hypothesis is that the source, ASKAP J1935+2148, could be a neutron star that emits radio signals as it rotates. If this is accurate, it would be the slowest spinning neutron star ever recorded by a significant margin, challenging current astrophysical models.

Unprecedented Pace

Neutron stars, the remnants of supernovae, are incredibly dense and possess powerful magnetic fields. These fields emit streams of particles, which, in pulsars, appear as repeating signals due to their rotation. Typical pulsars complete rotations in mere seconds, with the fastest known spinning at 716 times per second. In contrast, ASKAP J1935+2148's 54-minute interval is extraordinarily slow.

"It is highly unusual to discover a neutron star candidate emitting radio pulsations in this way," said Manisha Caleb, the study's lead author from the University of Sydney Institute for Astronomy. "The fact that the signal is repeating at such a leisurely pace is extraordinary."

Complex Emission Patterns

ASKAP J1935+2148 displays three distinct emission states: strong radio signals lasting 10 to 50 seconds, a weaker state with pulses 26 times fainter lasting a third of a second, and a quiescent state. Over eight months, researchers observed changes in the active emission states, suggesting physical alterations in the emitting region.

If not a neutron star, another possibility is a highly magnetic white dwarf, the most common type of stellar remnant. However, this theory also raises questions, as no similarly magnetized white dwarfs have been detected nearby, despite their expected power.

Further investigation of ASKAP J1935+2148 could potentially reshape our understanding of neutron stars and white dwarfs, as well as how they emit radio waves and their populations in the Milky Way.