The First Surface Map of a Neutron Star
Using data from the NICER X-ray telescope, two independent teams of researchers obtained a reliable estimate of the mass and radius of a neutron star about 1,000 light-years away from Earth. They also mapped its surface, discovering that the configuration of its magnetic field is very different from that hypothesized by theoretical models
The NICER X-ray telescope
Brought into orbit by a SpaceX Dragon spacecraft, the NICER X-ray telescope was installed outside the International Space Station in June 2017. The name, which stands for Neutron star Interior Composition ExploreR, is a precise reference to the task that this instrument has been performing for two years now. NICER records X-ray emissions from neutron stars, providing scientists with observational data to derive the radius and mass of these super-compact stellar remnants. These are essential parameters, which scientists use to obtain valuable information about the state of matter within neutron stars, whose nuclei reach pressures and densities that have no equal in any other celestial object accessible to the observation.