Early Planet Formation in Embedded Disks (eDisk) XII: Accretion streamers, protoplanetary disk, and outflow in the Class I source Oph IRS63

Abstract

We present ALMA observations of the Class I source Oph IRS63 in the context of the Early Planet Formation in Embedded Disks (eDisk) large program. Our ALMA observations of Oph IRS63 show a myriad of protostellar features, such as a shell-like bipolar outflow (in ${}^{12}$CO), an extended rotating envelope structure (in ${}^{13}$CO), a streamer connecting the envelope to the disk (in C${}^{18}$O), and several small-scale spiral structures seen towards the edge of the dust continuum (in SO). By analyzing the velocity pattern of ${}^{13}$CO and C${}^{18}$O, we measure a protostellar mass of ${\mathrm{M}}_{\star }=0.5\pm 0.2$~${\mathrm{M}}_{\odot }$ and confirm the presence of a disk rotating at almost Keplerian velocity that extends up to $\sim 260$ au. These calculations also show that the gaseous disk is about four times larger than the dust disk, which could indicate dust evolution and radial drift. Furthermore, we model the C${}^{18}$O streamer and SO spiral structures as features originating from an infalling rotating structure that continuously feeds the young protostellar disk. We compute an envelope-to-disk mass infall rate of $\sim 10^{-6}$~${\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$ and compare it to the disk-to-star mass accretion rate of $\sim 10^{-8}$~${\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$, from which we infer that the protostellar disk is in a mass build-up phase. At the current mass infall rate, we speculate that soon the disk will become too massive to be gravitationally stable.

26 pages and 17 figures