  We investigate the stellar atmospheres of the two components of the Herbig Ae
SB2 system AK Sco to determine the elements present in the stars and their
abundance. Equal stellar parameters T_eff = 6500K and log g = 4.5 were used for
both stars. We studied HARPSpol spectra (resolution 110,000) that were
previously used to state the presence of a weak magnetic field in the
secondary. A composite synthetic spectrum was compared in the whole observed
region lambda 3900-6912A with the observed spectrum. The abundances were
derived mostly from unblended profiles, in spite of their sparsity, owing to
the complexity of the system and to the not negligible v sin i of 18km/s and
21km/s adopted for the two components, respectively. The identified elements
are those typical of stars with spectral type F5IV-V, except for Li I at 6707A
and He I at 5875.61A, whose presence is related with the Herbig nature of the
two stars. Furthermore, overabundances were determined in both stars for Y, Ba,
and La. Zirconium is overabundant only in the primary, while sulfur is
overabundant outside the adopted error limits only in the secondary. In
contrast to previous results showing a high occurrence rate of lambda Boo
peculiarities or normal chemical composition among the Herbig Ae/Be stars, the
abundance pattern of AK Sco is similar to that of only few other Herbig stars
displaying weak Ap/Bp peculiarities. A few accretion diagnostic lines are
discussed.
