  In recent years a number of poorly studied chemical elements, such as
phosphorus, sulphur, and strontium, have received special attention as
important tracers of the Galactic chemical evolution. By exploiting the
capabilities of the infrared echelle spectrograph GIANO mounted at the
Telescopio Nazionale Galileo, we acquired high resolution spectra of four
Galactic dwarf stars spanning the metallicity range between about one-third and
twice the solar value. We performed a detailed feasibility study about the
effectiveness of the P, S, and Sr line diagnostics in the Y band between 1.03
and 1.10 microm. Accurate chemical abundances have been derived using
one-dimensional model atmospheres computed in local thermodynamic equilibrium
(LTE). We computed the line formation assuming LTE for P, while we performed
non-LTE analysis to derive S and Sr abundances. We were able to derive
phosphorus abundance for three stars and an upper limit for one star, while we
obtained the abundance of sulphur and strontium for all of the stars. We find
[P/Fe] and [S/Fe] abundance ratios consistent with solar-scaled or slightly
depleted values, while the [Sr/Fe] abundance ratios are more scattered (by
+/-0.2 dex) around the solar-scaled value. This is fully consistent with
previous studies using both optical and infrared spectroscopy. We verified that
high-resolution, Y-band spectroscopy as provided by GIANO is a powerful tool to
study the chemical evolution of P, S, and Sr in dwarf stars.
