Australian scientists from the University of Sydney and CSIRO have discovered a neutron star spinning slower than any previously measured, taking nearly an hour to complete a rotation. This unique find, published in Nature Astronomy, challenges current understanding of neutron star behavior.
Lead author Dr. Manisha Caleb from the University of Sydney Institute for Astronomy remarked, “It is highly unusual to discover a neutron star candidate emitting radio pulsations in this way. The fact that the signal is repeating at such a leisurely pace is extraordinary.”
Typically, neutron stars—stellar remnants of supernova explosions from stars about ten times the mass of the sun—rotate rapidly, completing a full spin in mere seconds. The newly discovered neutron star, however, defies this norm, emitting radio light at a pace too slow to align with existing models.
The discovery was made using CSIRO’s ASKAP radio telescope in Western Australia. Dr. Emil Lenc, co-lead author, highlighted ASKAP’s ability to scan large portions of the sky simultaneously, allowing researchers to detect unexpected anomalies. “We were simultaneously monitoring a source of gamma rays and seeking a fast radio burst when I spotted this object slowly flashing in the data,” he said.
The origin of the long-period signal remains a mystery, with white dwarfs and neutron stars being prime suspects. Dr. Caleb noted the object displays three distinct emission states, each with entirely different properties, making it even more intriguing. The MeerKAT radio telescope in South Africa helped differentiate these states, confirming the signals originated from the same point in the sky.
While a highly magnetic isolated white dwarf could potentially explain the observed signal, such objects have never been discovered nearby. Conversely, a neutron star with extreme magnetic fields could more elegantly account for the emissions observed.
