These are the first mappings of the surface of a Pulsar, a variety of neutron star, precisely PSR J0030 +0451.
They appear different because they were performed by two different research groups, who worked on the same data provided by the NICER X-ray telescope, installed in 2017 on the ISS.
One of the two groups concluded that there are two hotspots in the southern hemisphere, while the other believes there are three.
The star’s surface is subject to relativistic effects, such that part of the opposite hemisphere is visible in one hemisphere. As well as perturbed by the star’s still unclear internal dynamics and the magnetic field it generates.
The analyses have provided fascinating data on Pulsar, challenging everything we thought we knew, particularly the complexity of the magnetic field, which turns out (from one of the most accurate modeling) to be asymmetrical.