ARE MOLECULAR CLOUDS FORMED BY IMPACT OF HIGH-VELOCITY CLOUDS

We simulated collisions of High Velocity Clouds with the galactic disk with a simple hydrodynamical code. Main aspects of the morphology of nearby (d < 500 pc) cloud complexes, like the rho Oph, Orion and Tauru s-Auriga-Perseus complexes, are reproduced. These aspects include tota l mass, distance from the galactic plane, orientation of elongated gas structures with respect to the plane, and relative position of cluste rs of O-B stars with respect to the main concentrations of molecular g as. The space distribution of stars of different ages, usually explain ed in terms of sequential star formation, is interpreted in a new way in our model.