Sousa, S. G.Santos, N. C.Mayor, M.Udry, S.Casagrande, L.Israelian, G.Pepe, F.Queloz, D.Monteiro, M. J.P.F.G.2026-01-012026-01-010094-243XORCID:/0000-0003-2688-7511/work/162948990https://hdl.handle.net/1885/733798663We present a catalogue with accurate stellar parameters for the 451 stars that compose the HARPS Guaranteed Time Observations (GTO) "high precision" sample. We use our results, together with the others found in the literature, to study the metallicity-planet correlation, namely for very low mass planets. The results presented here suggests that contrarily to their jovian couterparts, neptune-like planets do not form preferentially around metal-rich stars. The ratio of jupiter-toneptunes is also an increasing function of stellar metallicity. These results are discussed in the context of the core-accretion model for planet formation.4enFormationFundamental parametersPlanetary systemsSpectroscopic parameters for 451 stars in the HARPS GTO planet search program: Stellar [fe/h] and the frequency of exo-neptunes200910.1063/1.309915264849086187