Few Tens au Scale Physical and Chemical Structures Around Young Low-Mass Protostars

This book characterizes the kinematic and chemical structures of disk-forming regions around low-mass protostellar sources and their interplay based on Atacama Large Millimeter/submillimeter Array (ALMA) observations. It describes the chemical evolution of molecules formed in an interstellar gas using the ALMA observations of 5 Sun-like protostars at a spatial resolution of a few tens au scale, which unveils the physical mechanism of star and planetary formation.The book reviews the author s successful works, focusing on two key findings: (i) A drastic change in the chemical composition of the gas around the centrifugal barrier of the infalling-rotating envelopes, and (ii) the chemical composition in the disk-forming regions, which varies from source to source depending on the chemical characteristics of the parent molecular cloud. These findings are based on the fine characterization of physical structures based on careful kinematic analyses. An additional attraction is theinclusion of the skillful reviews of ALMA observatory and its observation and physical models to describe the observed gas structure.