An Unbiased Chemistry Survey toward Embedded Protostars in the Perseus Star-forming Region

Planet formation may start during the embedded phase of star formation. In this scenario, the chemistry of embedded disks may directly determine the chemical composition of the forming planets. In recent years, observations discover several embedded protostars that have developed complex chemistry in the disk-forming region. However, only a few observations attempt to characterize the statistics of the abundance of complex molecules at embedded protostars and their relationships to star formation processes. I will present an overview results of complex organic molecules from the Perseus ALMA Chemistry Survey (PEACHES), which aims to unbiasedly survey the chemistry toward 50 embedded protostars with a spatial resolution comparable to the size of the disk-forming region. In PEACHES, we identify a variety of COMs, including CH₃OH, CH₃CN, CH₃OCHO, CH₃OCH₃, and C₂H₅OH. For the protostars with COMs, we find their column densities of COMs correlate well between species, hinting at common chemistry for Perseus protostars. Particularly, the abundance of CH₃OH tightly correlates with that of CH₃CN; however, a direct chemical link between these two molecules cannot be firmly established. Protostellar properties, such as bolometric luminosity and bolometric temperature, have little impact on the occurrence of complex organic molecules. The occurrence rate of different complex molecules learned from the PEACHES survey will provide a primer for constraining chemical evolution during the star formation.