  Hipparcos data provide the first, volume limited and absolute magnitude
limited homogeneous tracer of stellar density and velocity distributions in the
solar neighbourhood. The density of A-type stars more luminous than $M_v=2.5$
can be accurately mapped within a sphere of 125 pc radius, while proper motions
in galactic latitude provide the vertical velocity distribution near the
galactic plane. The potential well across the galactic plane is traced
practically hypothesis-free and model-free. The local dynamical density comes
out as $\rho_{0}=0.076 \pm0.015~M_{\sun}~{pc}^{-3}$ a value well below all
previous determinations leaving no room for any disk shaped component of dark
matter.
