  Aims. In this work we derive new precise and homogeneous parameters for 37
stars with planets. For this purpose, we analyze high resolution spectra
obtained by the NARVAL spectrograph for a sample composed of bright planet host
stars in the northern hemisphere. The new parameters are included in the
SWEET-Cat online catalogue. Methods. To ensure that the catalogue is
homogeneous, we use our standard spectroscopic analysis procedure, ARES+MOOG,
to derive effective temperatures, surface gravities, and metallicities. These
spectroscopic stellar parameters are then used as input to compute the stellar
mass and radius, which are fundamental for the derivation of the planetary mass
and radius. Results. We show that the spectroscopic parameters, masses, and
radii are generally in good agreement with the values available in online
databases of exoplanets. There are some exceptions, especially for the evolved
stars. These are analyzed in detail focusing on the effect of the stellar mass
on the derived planetary mass. Conclusions. We conclude that the stellar mass
estimations for giant stars should be managed with extreme caution when using
them to compute the planetary masses. We report examples within this sample
where the differences in planetary mass can be as high as 100% in the most
extreme cases.
