Early Planet Formation in Embedded Disks (eDisk). Accretion streamers, Keplerian disk, and outflow in the protostar Oph IRS63

Christian Alejandro Flores Gonzalez, Nagayoshi Ohashi, John J. Tobin, Jes Kristian Jorgensen, eDisk Team

We present ALMA observations of the Class I source Oph IRS63 in the context of the Early Planet Formation in Embedded Disks (eDisk) program. Our ALMA observations of Oph IRS63 show a myriad of protostellar features, such as a shell-like bipolar outflow (in 12CO), an extended rotating envelope (in 13CO), a large-scale streamer connecting the envelope to the disk (in C18O), and several small-scale spiral structures seen towards the edge of the dust continuum (in SO). By analyzing the velocity pattern of 13CO and C18O, we measure a central protostellar mass of ~0.5 Msun and confirm the presence of a Keplerian rotating disk extending up to ~250 au. These calculations show that the gaseous disk is about 3 times larger than the dust disk, similar to measurements in the more evolved Class II disks. Furthermore, we model the C18O streamer and SO spiral structures as features originating from an infalling rotating structure that continuously feeds the young protostellar disk. We computed the envelope-to-disk mass infall rate and compared it to the disk-to-star mass accretion rate, from which we inferred that the protostellar disk is in a mass build-up phase. At the current mass infall rate, we speculate that the disk might soon become too massive to be gravitationally stable.