Tentative detection of an outflow driven by an embedded protoplanet

Tomohiro Yoshida  (NAOJ)

The core accretion scenario of gas giant planet formation predicts gas accretion from a protoplanetary disk to onto protoplanets. As an analogy to the protostellar accretion and protostellar outflow, it has been proposed that an outflow can be driven by a protoplanet. We found that archival observations of the nearest protoplanetary disk around TW Hya exhibit potential evidence of molecular outflow in two separate SO lines. The SO emission is localized in the south-east part of the disk but detected up to ~60 au and aligned in a straight line. There appear to be at least three SO clumps, which resemble the “knotty” structure of protostellar outflows. The velocity with respect to the disk is ~5 km/s, which significantly deviates from the disk emission. The launching point of the outflow feature matches a dust gap in the protoplanetary disk, suggesting that the outflow is launched by an embedded protoplanet. If this is the case, the protoplanet mass is estimated to be ~6 Earth mass, which is roughly consistent with the mass estimate from the gap depth.