Which are the youngest protostars? Determining properties of confirmed and candidate Class 0 sources by broadband photometry

We searched the literature to obtain a complete list of known Class 0 sources. A list of 95 confirmed or candidate objects was compiled. To the best of our knowledge, all published broadband observations from 1 mum to 3.5 mm have been collected and are assembled in a catalog. These data were used to determine physical properties (T-bol, L-bol, L-smm/L-bol, M-env) and for a uniform classification. Fifty sources possess sufficient observational data and are classified as Class 0 or Class 0/1 objects. The source properties are compared with different evolutionary models to infer ages and masses, and their correlations are investigated. About 25% of the sources are found to be in a quiet accretion phase or possess a significantly different time evolution of the accretion rate than the average. In Taurus, with its isolated star formation mode, this seems especially to be the case.