Astronomers have made a fascinating discovery of a radio transient unlike anything they have seen before. These bursts of radio waves, known as “radio transients,” are typically emitted by rotating neutron stars called pulsars. However, the newly discovered radio transient, named ASKAP J1935+2148, has a cycle almost an hour long, the longest ever observed. It also emits different types of signals, including long, bright flashes, fast, weak pulses, and sometimes nothing at all.
The discovery was made using CSIRO’s ASKAP radio telescope in Western Australia, which has a wide field of view and is well-suited for detecting new phenomena. The signal from ASKAP J1935+2148 stood out because it was made up of “circularly polarised” radio waves, meaning the direction of the waves corkscrews as the signal travels through space.
Further observations were conducted using ASKAP and the MeerKAT radio telescope in South Africa. ASKAP J1935+2148 belongs to a new class of long-period radio transients, with only two others ever found. Its 53.8 minute period is by far the longest observed. The object exhibits three distinct states or modes: bright, linearly polarised pulses lasting from 10 to 50 seconds, weaker, circularly polarised pulses lasting about 370 milliseconds, and a quiet state with no pulses.
The origin of this signal with such a long period remains a mystery, but a slow-spinning neutron star is the leading explanation. However, the possibility that it could be a white dwarf cannot be ruled out. The object may be part of a binary system where it orbits another unseen star.
This discovery challenges our current understanding of neutron stars and white dwarfs and could provide valuable insights into the physics of these extreme objects. Further research is needed to confirm the nature of ASKAP J1935+2148 and explore the possibility of similar objects in our galaxy.