Context : The HARPS high-resolution high-accuracy spectrograph was made available to the astronomical community in the second half of 2003 .
Since then , we have been using this instrument for monitoring radial velocities of a large sample of Solar-type stars ( \simeq 1400 stars ) in order to search for their possible low-mass companions .

Aims : Amongst the goals of our survey , one is to significantly increase the number of detected extra-solar planets in a volume-limited sample to improve our knowledge of their orbital elements distributions and thus obtain better constraints for planet-formation models .

Methods : Radial-velocities were obtained from high-resolution HARPS spectra via the cross-correlation method .
We then searched for Keplerian signals in the obtained radial-velocity data sets .
Finally , companions orbiting our sample stars were characterised using the fitted orbital parameters .

Results : In this paper , we present the HARPS radial-velocity data and orbital solutions for 3 Solar-type stars : HD 100777 , HD 190647 , and HD 221287 .
The radial-velocity data of HD 100777 is best explained by the presence of a 1.16 M _ { Jup } planetary companion on a 384–day eccentric orbit ( e = 0.36 ) .
The orbital fit obtained for the slightly evolved star HD 190647 reveals the presence of a long-period ( P = 1038 d ) 1.9 M _ { Jup } planetary companion on a moderately eccentric orbit ( e = 0.18 ) . HD 221287 is hosting a 3.1 M _ { Jup } planet on a 456–day orbit .
The shape of this orbit is not very well-constrained because of our non-optimal temporal coverage and because of the presence of abnormally large residuals .
We find clues that these large residuals result from spectral line-profile variations probably induced by processes related to stellar activity .

Conclusions :