Using Relativistic Raytracing &X-Rays To See Detail on Surface Of Neutron Star
Neutron Stars are so small and distant that no conventional telescope could ever resolve their surfaces, but by using precise X-Ray timing and energy information it's possible to build models of the neutron star and figure out what the surface must look like.
Neutron Star Graphics from
Space Engine
Universe Sandbox
Elite: Dangerous
NASA https://svs.gsfc.nasa.gov/13240
Most of the diagrams are from the paper:
NICER VIEW OF PSR J0030+0451: MILLISECOND PULSAR PARAMETER ESTIMATIONT. E. Riley,1A. L. Watts,1S. Bogdanov,2P. S. Ray,3R. M. Ludlam,4, 5S. Guillot,6, 7Z. Arzoumanian,8C. L. Baker,9A. V. Bilous,1D. Chakrabarty,10K. C. Gendreau,8A. K. Harding,11W. C. G. Ho,12, 13J. M. Lattimer,14S. M. Morsink,15and T. E. Strohmayer
Available at: https://arxiv.org/pdf/1912.05702.pdf
This is one of several papers on NICER in the latest issue of the Astronomical Journal Letters
https://iopscience.iop.org/journal/2041-8205