The chemical composition of the oldest nearby open cluster Ruprecht 147
  Rup147 is the closest old open cluster, with a distance of less than 300 pc
and an age of about 2.5Gyr. It is therefore well suited for testing stellar
evolution models and for obtaining precise and detailed chemical abundance
information. We combined photometric and astrometric information coming from
literature and the Gaia mission with very high-resolution optical spectra of
stars in different evolutionary stages to derive the cluster distance, age, and
detailed chemical composition. We obtained spectra of six red giants using
HARPS-N at the TNG. We also used ESO archive spectra of 22 main sequence stars,
observed with HARPS at the 3.6m telescope. The very high resolution (115000)
and the large wavelength coverage (about 380-680nm) of the twin instruments
permitted us to derive atmospheric parameters, metallicity, and detailed
chemical abundances of 23 species from all nucleosynthetic channels. We
employed both equivalent widths and spectrum synthesis. We also re-derived the
cluster distance and age using Gaia parallaxes, proper motions, and photometry
in conjunction with the PARSEC stellar evolutionary models. We fully analysed
those stars with radial velocity and proper motion/parallax in agreement with
the cluster mean values. We also discarded one binary not previously
recognised, and six stars near the MS turn-off because of their high rotation
velocity. Our final sample consists of 21 stars (six giants and 15 MS stars).
We measured metallicity (the cluster average [Fe/H] is +0.08, rms=0.07) and
abundances of light, {\alpha}, Fe-peak, and neutron-capture elements. The Li
abundance follows the expectations, showing a tight relation between
temperature and abundance on the MS, at variance with M67, and we did not
detect any Li-rich giant. We confirm that Rup147 is the oldest nearby open
cluster. This makes it very valuable to test detailed features of stellar
evolutionary models.
