Rapid Formation of Molecular Clouds and Stars in the Solar Neighborhood

摘要

We show how molecular clouds in the solar neighborhood might be formed and produce stars rapidly enough to explain stellar population ages, building on results from numerical simulations of the turbu- lent interstellar medium and general considerations of molecular gas formation. Observations of both star-forming regions and young, gas-free stellar associations indicate that most nearby molecular clouds form stars only over a short time span before dispersal; large-scale flows in the diffuse interstellar medium have the potential for forming clouds sufficiently rapidly and for producing stellar populations with ages much less than the lateral crossing times of their host molecular clouds.