  To understand the formation and evolution of solar-type stars in the solar
neighborhood, we need to measure their stellar parameters to high accuracy. We
present a catalogue of accurate stellar parameters for 451 stars that represent
the HARPS Guaranteed Time Observations (GTO) ``high precision'' sample.
Spectroscopic stellar parameters were measured using high signal-to-noise (S/N)
spectra acquired with the HARPS spectrograph. The spectroscopic analysis was
completed assuming LTE with a grid of Kurucz atmosphere models and the recent
ARES code for measuring line equivalent widths. We show that our results agree
well with those ones presented in the literature (for stars in common). We
present a useful calibration for the effective temperature as a function of the
index color B-V and [Fe/H]. We use our results to study the metallicity-planet
correlation, namely for very low mass planets. The results presented here
suggest that in contrast to their jovian couterparts, Neptune-like planets do
not form preferentially around metal-rich stars. The ratio of
jupiter-to-neptunes is also an increasing function of stellar metallicity.
These results are discussed in the context of the core-accretion model for
planet formation.
