Abstract
From Hipparcos distances and proper motions for approximately 22000 stars we described the residual velocity distribution by the superposition of two Gaussians instead one as traditionally used. The sample of stars was selected by magnitude, color, Galactic position and distance and ranged in 6 spectral-type groups, 3 of early-type and 3 of late-type stars. We verified that for the early-type stars no gain is attained with our representation but for the late-type stars it is clear that the superposition of two Gaussians better describe the velocity distribution. Our results clearly point to the existence of two different kinematic populations very well characterized in the three late-type star groups: one population with high velocity dispersion and another with low velocity dispersion. It is still more interesting since the high and the low velocity dispersion population is the same in all the three groups. The core of this work was published in De Souza & Teixeira 2007.
