  Precise radial-velocity observations at Haute-Provence Observatory (OHP,
France) with the ELODIE echelle spectrograph have been undertaken since 1994.
In addition to several discoveries described elsewhere, including and following
that of 51 Peg b, they reveal new sub-stellar companions with essentially
moderate to long periods. We report here about such companions orbiting five
solar-type stars (HD 8574, HD 23596, HD 33636, HD 50554, HD 106252) and one
sub-giant star (HD 190228). The companion of HD 8574 has an intermediate period
of 227.55 days and a semi--major axis of 0.77 AU. All other companions have
long periods, exceeding 3 years, and consequently their semi-major axes are
around or above 2 AU. The detected companions have minimum masses m2sini
ranging from slightly more than 2 M_Jup to 10.6 M_Jup. These additional objects
reinforce the conclusion that most planetary companions have masses lower than
5 M_Jup but with a tail of the mass distribution going up above 15 M_Jup. The
orbits are all eccentric and 4 out of 6 have an eccentricity of the order of
0.5. Four stars exhibit solar metallicity, one is metal-rich and one
metal-poor. With 6 new extra-solar planet candidates discovered, increasing
their total known to-date number to 115, the ELODIE Planet Search Survey yield
is currently 18. We emphasize that 3 out of the 6 companions could in principle
be resolved by diffraction-limited imaging on 8m-class telescopes depending on
the achievable contrast, and therefore be primary targets for first attempts of
extra-solar planet direct imaging.
