The temperature of VFTS 1021 (O4 If+) is based on the lines N iii λ4634/4640 and N iv λ4058, and He i λ4471. Ṁ and He-abundance are based on He ii 2.19 μm and . The best fitting model Ṁ is too weak. The star suggests a unusually high N abundance. The fit quality is not good, but can be improved (see Fig. E.27). The He-abundance is between 25% and 32.5%. (Second panel: HST/FOS, third panel: ARGUS).