Thermal X-Ray Emission from Neutron Star Surfaces: Gravitational Redshift and the Radius Measurement Problem

This paper computes gravitational redshift and the radius measurement problem from stated published inputs, with every number produced by the deposited script. The headline results are: blackbody luminosity of a 12 km star at one million degrees = 1.03e+33 erg/s, gravitational redshift of a 1.4 solar mass star of radius 12 km = 0.235, temperature seen at infinity for a surface at one million degrees = 8.10e+05 K, apparent radius seen at infinity for a 12 km star = 14.8 km, compactness 2GM/Rc^2 for the 1.4 solar mass 12 km case = 0.345, flux at Earth from the million-degree 12 km star at one kiloparsec = 8.58e-12 erg/cm^2/s. The calculation is a computation from standard plasma and gravitation physics applied to values reported by Chandra, XMM-Newton and eROSITA studies; it is simulated and computed, not measured. The inputs, the formulae and the sensitivity of each result to its assumptions are stated in full, so that the arithmetic can be checked, rerun with different inputs, and used as a reference for the systems concerned.