No other radio-emitting neutron star, out of the more than 3000 discovered so far, has been discovered rotating so slowly. The results are published today in Nature Astronomy.
Lead author Dr Manisha Caleb from the University of Sydney Institute for Astronomy said: “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.”
This unusual neutron star is emitting radio light at a rate that is too slow to fit with current descriptions of radio neutron star behaviour. This provides new insights into the complex life cycles of stellar objects.
At the end of their life, large stars about 10 times the mass of the Sun use up all their fuel and explode in a spectacular blast we call a supernova. What remains is a stellar remnant so dense that 1.4 times the mass of our Sun is packed into a ball just 20 kilometres across.
Matter is so dense that negatively charged electrons are crushed into positively charged protons and what’s left is an object made up of trillions of neutrally charged particles. A neutron star is born.
Given the extreme physics with which these stars collapse, neutron stars typically rotate mind-bendingly fast, taking just seconds or even fractions of a second to fully spin on their axis.
Now, astronomers at the University of Sydney and CSIRO have discovered a compact object repeating its signal with a comparatively leisurely period just shy of one hour.
The discovery was made using CSIRO’s ASKAP radio telescope on Wajarri Yamaji Country in Western Australia.
The ASKAP radio telescope can see a large part of the sky at once, which means it can capture things researchers aren’t even looking for. CSIRO scientist Dr Emil Lenc, co-lead author on the paper, said they wouldn’t have found this strange object if it wasn’t for ASKAP’s unique design.
