An accurate and self-consistent chemical abundance catalogue for the
  APOGEE/Kepler sample
  Context. The APOGEE survey has obtained high-resolution infrared spectra of
more than 100,000 stars. Deriving chemical abundances patterns of these stars
is paramount to piecing together the structure of the Milky Way. While the
derived chemical abundances have been shown to be precise for most stars, some
calibration problems have been reported, in particular for more metal- poor
stars. Aims. In this paper, we aim to (1) re-determine the chemical abundances
of the APOGEE+Kepler stellar sample (APOKASC) with an independent procedure,
line list and line selection, and high quality surface gravity information from
astroseismology, and (2) extend the abundance catalogue by including abundances
that are not currently reported in the most recent APOGEE release (DR12).
Methods. We fixed the Teff and log g to those determined using
spectrophotometric and asteroseismic techniques, respectively. We made use of
the Brussels Automatic Stellar Parameter (BACCHUS) code to derive the
metallicity and broadening parameters for the APOKASC sample. In addition, we
derived differential abundances with respect to Arcturus. Results. We have
validated the BACCHUS code on APOGEE data using several well-known stars, and
stars from open and globular clusters. We also provide the abundances of C, N,
O, Mg, Ca, Si, Ti, S, Al, Na, Ni, Mn, Fe, K, P, Cr, Co, Cu, Rb, Yb and V for
every star, line, and show the impact of line selection on the final
abundances. These include abundances of five new elements and improved
abundances for Si, Ti, S, and V. Conclusions. In this paper, we present an
independent analysis of the APOKASC sample and provide abundances of up to 21
elements. This catalogue can be used not only to study chemical abundance
patterns of the Galaxy but also to train data driven spectral approaches which
can improve the abundance precision in a restricted dataset, but also full
APOGEE sample.
