|
We present a census of the population of deeply embedded young stellar objects in the Perseus and Ophiuchus molecular cloud complexes based on combinations of Spitzer Space Telescope mid-infrared data from the "Cores to Disks" (c2d) legacy team and JCMT/SCUBA submillimeter maps from the COMPLETE team. We construct unbiased samples of protostars based on the mid-infrared colors of the Spitzer sources and the concentrations of the SCUBA cores. For Perseus in particular, the mid-infrared sources with 24 micron detections and red [3.6]-[4.5] colors are located close to the center of the SCUBA cores, typically within a few thousand AU of their peaks. The narrowness of the spatial distribution of mid-infrared sources around the peaks of the SCUBA cores suggests that no significant dispersion of the newly formed YSOs has occurred. This argues against the suggestion that motions of protostars regulate the time scales over which significant (Bondi-Hoyle) accretion can occur. We use the samples of YSOs to compare the time scales for evolution through the pre and protostellar stages and to estimate the star formation efficiencies of each of the two clouds.
|
