Astronomy Colloquium

Abstract:  While the stages in the formation of stellar systems are now well charted, uncertainties in the initial conditions and evolution lead to stellar systems with a diverse array of architectures.  In this talk I will discuss the major stages in the evolution of young stellar objects, starting from the young protostars and ending in stars that have dispersed all circumstellar material.  At each step I will describe insights into some of the relevant processes that are being obtained from ongoing observational programs.  For protostars, we are pursuing the first long-term monitoring program in the sub-mm to establish the role of accretion variability during the main phase of stellar growth.  The next stage, protoplanetary disks, is now being revolutionized by exquisite ALMA images of substructures, which point to the presence of hidden planets.  Finally, once the star, better descriptions of stellar properties is needed to fulfill the promise of Gaia in revealing the recent star formation in our local neighborhood.