Probing Complex Structures of the Protostellar Envelope Driven by the Interplay of Mass Inflow/Outflow and Magnetic Field

ABSTRACT :
Over more than a decade of observations with ALMA, the detailed structure of the envelopes of Class 0/I protostars has been revealed, showing phenomena/structures that cannot be explained by the classical picture of star formation. These features suggest that complex gas dynamics in the parent core and disks, coupled with interactions with magnetic fields, play a critical role in the deeply embedded phase. Through extensive ALMA data analysis, including archival data, we have identified several types of outflows and envelopes. Multiple (or secondary) outflows from a possible single stellar system are crucial for studying the dynamic variations in mass accretion (Sato et al. 2023, ApJ, 958, 102). We also found the presence of crescent-shaped outflows, which provide insights into constraining the magnetically driven outflow model from a face-on perspective, which is a statistically rare sample (Harada et al. 2023, ApJ, 945, 63). In the Taurus and Corona Australis regions, we discovered spike- and ring-like structures extending from the protostellar disks on scales ranging from a few au to 7000 au, traced by high-density envelope tracers such as C18O and dust continuum (Tokuda et al. 2023, ApJL, 656, 16; 2024, ApJ, 965, 99). These structures are thought to be formed by the interchange instability, a type of magnetic buoyancy instability, which has been reproduced in numerical simulations. This talk will summarize our understanding of magnetic flux and mass transport based on these observations.