Chemical abundances of primary stars in the Sirius-like binary systems
  Study of primary stars lying in Sirius-like systems with various masses of WD
companions and orbital separations is one of the key aspects to understand the
origin and nature of Barium (Ba) stars. In this paper, based on high resolution
and high S/N spectra, we present systematic analysis of photospheric abundances
for 18 FGK primary stars of Sirius-like systems including six giants and 12
dwarfs. Atmospheric parameters, stellar masses, and abundances of 24 elements
(C, Na, Mg, Al, Si, S, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Sr, Y, Zr, Ba,
La, Ce and Nd) are determined homogeneously. The abundance patterns in these
sample stars show that most of the elements in our sample follow the behavior
of field stars with similar metallicity. As expected, s-process elements in
four known Ba giants show overabundance. A weak correlation was found between
anomalies of s-process elemental abundance and orbital separation, suggesting
the orbital separation of the binaries could not be the main constraint to
differentiate strong Ba stars from mild Ba stars. Our study shows that the
large mass (>0.51 M ) of a WD companion in a binary system is not a sufficient
condition to form a Ba star, even if the separation between the two components
is small. Although not sufficient it seems to be a necessary condition since Ba
stars with lower mass WDs in the observed sample were not found. Our results
support that [s/Fe] and [hs/ls] ratios of Ba stars are anti-correlated with the
metallicity. However, the different levels of s-process overabundance among Ba
stars may not to be dominated mainly by the metallicity.
