Neutron Star Measures Just 22 Kilometers Across

How big is a neutron star? These extreme, ultra-dense collapsed stars are fairly small, as far as stellar objects are concerned. Even though they pack the mass of a full-sized star, their size is often compared to the width of a medium-to-large-sized city. For years, astronomers have pegged neutron stars at somewhere between 19-27 km (12 to 17 miles) across. This is quite actually quite precise, given the distances and characteristics of neutrons stars. But astronomers have been working to narrow that down to an even more precise measurement.

An international team of researchers has now done just that. Using data from several different telescopes and observatories, members of the Max Planck Institute for Gravitational Physics, theAlbert Einstein Institute (AEI) have narrowed the size estimates for neutron stars by a factor of two.

“We find that the typical neutron star, which is about 1.4 times as heavy as our Sun has a radius of about 11 kilometers,” said Badri Krishnan, who led the research team at the AEI Hannover. “Our results limit the radius to likely be somewhere between 10.4 and 11.9 kilometers.” That translates to between 20.8 – 23.8 km in diameter.

The object of this team’s study is rather famous: the binary neutron star merger GW170817 which created the gravitational waves detected in 2017 by the LIGO (Laser-Interferometer Gravitational Wave Observatory) and Virgo consortium. This object has been studied numerous times by multiple telescopes, including the Fermi satellite, the Hubble Space Telescope and other telescopes and observatories around the world. All those observations gave the Max Planck team a boatload of data to work with.

Source: “Neutron Star Measures Just 22 Kilometers Across” Universe Today, 28 February 2020.<>

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