Left-hand panel: synthetic X-ray unabsorbed flux (erg cm⁻² s⁻¹) and luminosity (erg ⁻¹) plot of the Bubble Nebula as it evolves in time (Myr). Seven X-ray bands simulated from soft to hard X-rays, including 0.1 keV, 0.2 keV, 0.5 keV, 1 keV, 2 keV, 5 keV, and 10 keV. Right-hand panel: absorbed flux (erg cm⁻² s⁻¹) and luminosity (erg s⁻¹) plot showing that the 0.1 keV–1 keV X-ray bands get absorbed by the ISM. Mechanical luminosity of the stellar wind (i.e. energy input rate to the wind bubble) is (seen as the black line in both plots).