sentences:  Hard x-ray radiation from the vicinity of Pismis 24-1 is assumed to be caused by the colliding winds of these two supergiants.Pismis 24-1SW is apparently a single star with a spectral type of O4 III(f+), indicating a temperature around 40,000 K and emission lines of ionised nitrogen, silicon, and helium.The luminosity is around , the radius , and the mass .