Gould's belt and beyond - Comparing models with observations

The motion of OB stars closer than 2 kpc from the Sun is analysed. It shows that the local system of young stars lags behind the LSR by 4-5 km s(-1), and that its motion may be explained as local nearly rigid-body rotation in the same direction as the overall galactocentric rotation. The residual ve locities reveal local expansions in the Scorpius-Centaurus and Orion region s and a motion of these two regions away from each other. The computed orbi ts show that 10-12 Myr ago the progenitors of Scorpius-Centaurus OB associa tions were concentrated within a minimum volume. They were also closer to t he progenitors of the OB association in Orion, residing all together within a sheet-like region elongated in the l = 20-200 degrees direction. Free ex pansion, supershells related to OB associations and a supershell related to a hypernova event have been examined as possible models. No agreement with observation has been reached yet; more variants should be tested in the fu ture.