Spectral fit results of the NICER data. From top to bottom: model parameter evolution is shown for the abundance of lighter elements (lighter than magnesium all fixed to the same value), heavier elements (Mg, Al, Si, S, and Cl/Ar/Ca displayed with different colors), line energies for the emission/absorption lines (displayed with different colors), the photon power law index (Γ), ionization parameter (log ξ), the corresponding fit quality (χ²/d.o.f.), and the absorbed 1–10 keV flux density with the colored letters corresponding to spectra shown in Fig. 6. The alternate shading shows the times of the different decay phases.