Star formation history written in spectra

In this thesis, the process of star formation is mapped from large to small scales, using the world's most advanced observatories. Discoveries of several young stars with peculiar environments are reported. Dynamics of circumstellar gas and dust are analyzed in a diverse ensemble of young stars. The history of their formation process, impossible to probe directly, is revealed by spectroscopy. Among the outstanding problems addressed are the origin of jets, the scaling of accretion with stellar mass, and the variability of the accretion process. The star formation process from large to small scale. First, we describe a typical birth environment: a star cluster. We then zoom in on a number of individual systems in this and other star formation regions. The components which make up these objects are the topics of the other chapters: the disk, jets, and finally the young star itself. Throughout, the direct environment of the star is treated as a crime scene. We use it to derive how the star was formed and which stage of its life (or evolution) it has reached. The goal is to describe the formation and evolution of stars as a function of their mass and their surroundings.