Pulses from a rapidly spinning neutron star are delayed slightly as they head toward Earth, passing through the distorted space around a companion white dwarf. That delay allowed researchers to calculate the mass of the pulsar. Image: BSaxton, NRAO/AUI/NSF
Astronomers have found the most massive neutron star yet discovered, a rapidly rotating pulsar orbiting in lockstep with a white dwarf that crams 2.17 solar masses into a city-size sphere just 30 kilometres (18.6 miles) across. The pulsar appears to be close to the tipping point between matter’s ability to resist the crush of gravity versus collapse into a black hole.
“Neutron stars are as mysterious as they are fascinating,” said Thankful Cromartie, a graduate student at the University of Virginia and a pre-doctoral fellow at the National Radio Astronomy Observatory in Charlottesville, Virginia. She is first author of a paper accepted by Nature Astronomy.
“These city-sized objects are essentially ginormous atomic nuclei. They are so massive that their interiors take on weird properties. Finding the maximum mass that physics and nature will allow can teach us a great deal about this otherwise inaccessible realm in astrophysics.”
Neutron stars and their fast-spinning cousins – pulsars – are formed in supernova explosions ...