Neutron stars typically spin quickly, taking just a few seconds or even a fraction of a second to complete one revolution around their axis, but one neutron star labeled ASKAP J1935+2148 bucks this rule, emitting radio signals at a relatively slow interval of 53.8 minutes.
“We're used to extreme examples when studying radio-emitting neutron stars, so the discovery of such a compact star that is still emitting radio waves despite rotating slowly was unexpected,” said Professor Ben Stappers, from the University of Manchester.
“This new generation of radio telescopes demonstrates that pushing the boundaries of our search space will reveal surprises that will shake up our understanding.”
At the end of their lives, massive stars use up all their fuel and undergo a spectacular explosion called a supernova.
What remains is a stellar remnant called a neutron star, which consists of trillions of neutrons packed into an extremely dense sphere with a mass 1.4 times that of the Sun, packed into a radius of just 10 km.
Astronomers detected an unexpected radio signal from ASKAP J1935+2148 that traveled about 16,000 light-years to Earth.
The nature of its radio emission and the rate of change of its rotation period suggest that it is a neutron star, but further study is needed to confirm what this object is.
“This discovery relied on the complementary capabilities of the ASKAP and MeerKAT telescopes, combined with our ability to probe these objects on timescales of minutes, and examine how their radiation changes from second to second,” said Dr Kaustubh Rajwade, an astronomer at the University of Oxford.
“Such synergies can shed new light on how these compact objects evolve.”
ASKAP J1935+2148 was detected by CSIRO's ASKAP radio telescope in the Wadjari Yamatji region of Western Australia.
“What's interesting is that this object exhibits three different radiation states, each with completely different properties to the others,” said Dr Manisha Caleb, an astronomer at the University of Sydney.
“The MeerKAT radio telescope in South Africa played a key role in distinguishing between these states.”
“If the signals had not come from the same point in the sky, it would be hard to believe that it was the same object producing these different signals.”
“Until the arrival of these new telescopes, the dynamic radio sky was relatively unexplored,” said Professor Tara Murphy, from the University of Sydney.
“Now we can look deeply and frequently see a variety of unusual phenomena.”
“These events give us insight into how physics works in extreme environments.”
This discovery paper In the journal Natural Astronomy.
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M. Caleb othersA radio transient phenomenon in which the radiation state switches with a period of 54 minutes. Nat AstronPublished online June 5, 2024; doi: 10.1038/s41550-024-02277-w
Source: www.sci.news
