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(Abridged) Recent surveys of young star formation regions have shown that theaverage Class II object does not have enough dust mass to make the cores ofgiant planets. Younger Class 0/I objects have enough dust in their embeddeddisk, which begs the questions: can the first steps of planet formation occurin these younger systems? The first step is building the first planetesimals,generally believed to be the product of the streaming instability. Hence thequestion can be restated: are the physical conditions of embedded disksconducive to the growth of the streaming instability? Here we model thecollapse of a `dusty' proto-stellar cloud to show that if there is sufficientdrift between the falling gas and dust, regions of the embedded disk can becomesufficiently enhanced in dust to drive the streaming instability. We includefour models, three with different dust grain sizes and one with a differentinitial cloud angular momentum to test a variety of collapse trajectories. Wefind a `sweet spot' for planetesimal formation for grain sizes of a few 10s ofmicron since they fall sufficiently fast relative to the gas to build a highdust-to-gas ratio along the disk midplane, but have slow enough radial driftspeeds in the embedded disk to maintain the high dust-to-gas ratio. Unlike thegas, which is held in hydrostatic equilibrium for a time due to gas pressure,the dust can begin collapsing from all radii at a much earlier time. Thestreaming instability can produce at least between 7-35 M$_\oplus$ ofplanetesimals in the Class 0/I phase of our smooth embedded disks, depending onthe size of the falling dust grains. This first generation of planetesimalscould represent the first step in planet formation, and occurs earlier in thelifetime of the young star than is traditionally thought.

Early planet formation in embedded protostellar disks: Setting the stage for the first generation of planetesimals