The availability of the Hipparcos Catalogue triggered many kinematic and
dynamical studies of the solar neighbourhood. Nevertheless, those studies
generally lacked the third component of the space velocities, i.e., the radial
velocities. This work presents the kinematic analysis of 5952 K and 739 M
giants in the solar neighbourhood which includes for the first time radial
velocity data from a large survey performed with the CORAVEL
spectrovelocimeter. It also uses proper motions from the Tycho-2 catalogue,
which are expected to be more accurate than the Hipparcos ones. The UV-plane
constructed from these data for the stars with precise parallaxes reveals a
rich small-scale structure, with several clumps corresponding to the Hercules
stream, the Sirius moving group, and the Hyades and Pleiades superclusters. A
maximum-likelihood method, based on a bayesian approach, has been applied to
the data, in order to make full use of all the available stars and to derive
the kinematic properties of these subgroups. Isochrones in the
Hertzsprung-Russell diagram reveal a very wide range of ages for stars
belonging to these groups. These groups are most probably related to the
dynamical perturbation by transient spiral waves rather than to cluster
remnants. A possible explanation for the presence of young clusters in the same
area of the UV-plane is that they have been put there by the spiral wave
associated with their formation, while the kinematics of the older stars of our
sample has also been disturbed by the same wave. The term "dynamical stream"
for the kinematic groups is thus more appropriate than the traditional term
"supercluster" since it involves stars of different ages, not born at the same
place nor at the same time.Comment: 22 pages, 16 figures, accepted for publication in A&