  (Abridged) To this purpose, in the course of the thesis work we prepared a
suitable software in order to use the same spectra acquired for radial velocity
determinations (i.e., with the spectrum of the Iodine cell imprinted on) to
measure variations of the stellar line profiles. This is a novel approach, that
can be of general utility in all high precision radial velocity surveys based
on iodine cell data. This software has then been extensively used on data
acquired within our survey, allowing a proper insight into a number of
interesting cases, where spurious estimates of the radial velocities due to
activity or contamination by light from the companions were revealed. The same
technique can also be considered to correct the measured radial velocities, in
order to search for planets around active stars.
