Resolving the Circumstellar Disk Around the Massive Protostar Driving the HH 80-81 Jet

TL;DR

This study uses high-resolution radio and submillimeter observations to resolve a circumstellar disk around a massive protostar, providing insights into the disk's structure and rotation.

Contribution

First high-resolution imaging of a ~200 AU circumstellar disk around a massive protostar, combining continuum and molecular line data.

Findings

Resolved a compact accretion disk of ~200 AU radius.

Detected rotation consistent with a circumstellar disk.

Differentiated free-free and dust emission contributions.

Abstract

We present new high-angular resolution observations toward the driving source of the HH 80-81 jet (IRAS 18162-2048). Continuum emission was observed with the Very Large Array at 7 mm and 1.3 cm, and with the Submillimeter Array at 860 microns, with angular resolutions of ~0"1 and ~0"8 respectively. Submillimeter observations of the sulfur oxide (SO) molecule are reported as well. At 1.3 cm the emission traces the well-known radio jet, while at 7 mm the continuum morphology is quadrupolar and seems to be produced by a combination of free-free and dust emission. An elongated structure perpendicular to the jet remains in the 7 mm image after subtraction of the free-free contribution. This structure is interpreted as a compact accretion disk of ~200 AU radius. Our interpretation is favored by the presence of rotation in our SO observations observed at larger scales. The observations presented here add to the small list of cases where the hundred-AU scale emission from a circumstellar disk around a massive protostar has been resolved.