Sub-millimeter wavelength protostellar accretion rate monitoring with AtLAST

How a star forms is a fundamental question in astrophysics. In the earliest stages of protostellar evolution high extinction prevents a direct study of the accretion processes and their temporal evolution. Monitoring the variations of the accretion luminosity in a large protostar sample over decades is needed to reveal how protostars accrete – in major bursts or in a quasi-steady fashion. We here argue that a large ground based sub-millimeter single-dish facility with a wide FoV is required to fulfill this task.