Birth Sites of Young Stellar Associations and Recent Star Formation in a
  Flocculent Corrugated Disk
  With backwards orbit integration we estimate birth locations of young stellar
associations and moving groups identified in the solar neighborhood that are
younger than 70 Myr. The birth locations of most of these stellar associations
are at smaller galactocentric radius than the Sun, implying that their stars
moved radially outwards after birth. Exceptions to this rule include are the
Argus and Octans associations which formed outside the Sun's Galactocentric
radius. Variations in birth heights of the stellar associations suggest that
they were born in a corrugated disk of molecular clouds, similar to that
inferred from the current filamentary molecular cloud distribution and dust
extinction maps. Multiple spiral arm features with different but near
corotation pattern speeds and at different heights could account for the
stellar association birth sites. We find that the young stellar associations
are located in between peaks in the UV stellar velocity distribution for stars
in the solar neighborhood. This would be expected if they were born in a spiral
arm which perturbs stellar orbits that cross it. In contrast, stellar
associations seem to be located near peaks in the vertical phase space
distribution, suggesting that the gas in which stellar associations are born
moves vertically together with the low velocity dispersion disk stars.
