A spinning cosmic carcass is all that remains of a weighty star hovering about 4,600 light-years from Earth after an explosive death. Now astronomers have discovered that this corpse is the most massive neutron star ever discovered.
In fact, they say that it is so massive – about 2.14 times the mass of our Sun that is packed into a sphere of about 20 kilometers in diameter – that it is almost at the limit of viability.  This neutron star, named J0740 + 6620, emits beacons with radio waves and rotates 289 times per second, turning it into a pulsar. The new estimate for the mass of the pulsar makes it stronger than the previous record holder ̵
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Scientists discovered the possibility of examining the corpse of a star in data collected by radio telescopes at the Green Bank Observatory and the Arecibo Observatory. The data came from a collaboration called NANOGrav, the North American Nanohertz gravitational wave observatory, with the goal of observing a series of these fast-spinning pulsars across the sky.
While looking at NANOGrav datasets, Cromartie and her team saw "a hint" on a physical phenomenon that would enable them to predict the mass of the pulsar. With the Green Bank Telescope in West Virginia, they then sought out this "hint" in more detail.
The astronomers found that the radio waves emitted by him regularly, based on the position of the pulsar, should reach the telescope earlier than expected they actually did. This physical phenomenon, called the Shapiro Delay, occurs when another celestial object orbits a rotating neutron star bound by the star's gravity. When the object, in this case a white dwarf star, passes in front of the pulsar, the orbiting object slightly warps the space around which the radio signal would move, causing the radio waves to arrive at our telescopes with some delay.
This is used by scientists These delays in calculating the mass of both the pulsar and the white dwarf.
The recent discovery could provide more information on supernovae and the formation of neutron stars Cromartie said. When large stars die, they typically detonate as supernovae. Such an explosion collapses the star and becomes either a neutron star or, if it is truly massive, a black hole.
There is a limit to how massive neutron stars can be, Cromartie said. In 2017 researchers reported that a star, once it reaches 2.17 times the mass of the sun, is condemned to a dark existence as a matter-hungry black hole. This suggests that J0740 + 6620 "really crosses that line," Cromartie said. Even more massive and the star would have collapsed into a black hole.
It is believed that some really crazy physics occurs in such dense star objects: "The physics occurring inside the stars is still very poorly understood." She said. Adding it close to the limit of existence could tell more about what's going on inside, but also about how high-density materials behave, she added, adding space for a degree in nuclear physics, "she added Pulsar used telescopes such as the Canadian Hydrogen Intensity Mapping Experiment Telescope (CHIME) and NASA's Neutron Star Interior Composition Explorer Telescope (NICER), which flies aboard the International Space Station to observe more regularly, allowing them to refine mass measurements.
The scientists reported their findings on September 16 in the journal Nature Astronomy .
Originally published on Live Science .