Positions of the source in the T_eff − log g plane according to different eRASS observations (red circles with the number 1 and 2), and according to joint fit (red empty circles), see Table 3. The XMM spectrum fit with fixed N_H is shown by blue circle. Model dependencies for various WD masses, taken from Nomoto et al. (2007), are shown by black dashed curves. The numbers at the curves indicate WD masses (in solar masses). The lower boundary of the stable thermonuclear burning band is shown by the dashed red line. The Eddington limit for solar H/He abundances is shown by the blue dashed line.