Star formation in the nearest kpc: the Spitzer View
M. Dunham, N.J.Evans III, G.G. Fazio, R.A. Gutermuth, J.L. Hora, S.T. Megeath, P.C. Myers, D. Peterson
The Spitzer Space Telescope surveyed most of the molecular clouds within a kiloparsec of the Sun, yielding a sample of nearby young stars that is unprecedented in both size and completeness, and enabling statistically meaningful studies of young stars and their most fundamental properties: where they form and how they evolve. Global star formation efficiencies are low (3% - 6% cloud-wide). Young stellar object (YSO) surface densities range over 3 orders of magnitude within individual molecular clouds. Average YSO densities are not correlated with most global cloud properties (like total molecular gas mass or the number of young stars produced), but do show a dependence on the average gas density, as might be expected. The star formation rate − gas surface density relation is an order of magnitude larger than predicted from the Kennicutt relation used in extragalactic studies. New lifetimes have been derived for the empirical "classes" of young stars, based on their observed spectral energy distributions (often assumed to represent evolutionary state) for the more complete sample within 500 pc. I will present these and other results from the nearby cloud surveys and discuss how Herschel will deepen and extend what we've learned.