Early Planet Formation in Embedded Disks (eDisk): R CrA IRAS 32

Francisco Jose Encalada, Leslie Looney, Nagayoshi Ohashi, eDisk Team, John J. Tobin, Jes Kristian Jorgens

Very young binary systems form in situ, providing key clues to binary formation and evolution. We present a first look at the young, Class 0 binary protostellar system R CrA IRAS 32 from the Early Planet Formation in Embedded Disks (eDisk) ALMA large program, which observed the system in the 1.3 mm continuum emission, 12CO (2-1), 13CO (2-1), C18O (2-1), SO (65-54), and nine other molecular lines that trace disk, shocks, and outflows. With a continuum resolution of 0.03′′ (?5 au, assuming a distance of 150 pc), we characterize the newly discovered binary sources (separation of 207 au), their circumstellar disks, and possible circumbinary disk-like structure. The circumstellar disk radii are 31.7±0.4 and 26.9±0.3 au for sources A and B, respectively, and their circumstellar disk dust masses are 21.9±1.1 and 12.7±0.6 Earth Mass. The circumstellar disks, circumbinary structure, and the projected orbital plane are all well aligned with each other, indicating formation in an smooth, ordered process such as disk fragmentation. Spectral analysis of CO isotopologues reveals outflows that originate from both of the sources and from the circumbinary disk-like structure. Furthermore, we detect Keplerian rotation and infall in the CO isotopologues. Based on a position-velocity diagram analysis of C18O and ideal Keplerian rotation, we estimate protostar masses of 0.3 and 0.2 Solar Mass, respectively.