Abstract
AA DOR is an eclipsing, close, post common-envelope binary (PCEB) consisting of a sdOB primary star and an unseen secondary with an extraordinary small mass ( M[2] ≈ 0.066M⊙) - formally a brown dwarf (see Rauch 2004 for details). In a spectral analysis of AA DOR, Rauch (2000) determined T[eff] = 42 kK and logg = 5.2 (cgs). The determination of the components' masses by comparison of these results with evolutionary models of Driebe et al . (1998) shows a discrepancy to masses derived from radial-velocity and the eclipse curves (Hilditch et al . 2003) - logg = 5.5 would be necessary in order to achieve an intersection at M[1] ≈ 0.330M⊙.
