A multiwavelength analysis of the spiral arms in the protoplanetary disk around WaOph 6

TL;DR

This study combines multiwavelength observations and simulations to analyze spiral structures in the protoplanetary disk around WaOph 6, aiming to determine whether planetary perturbations or gravitational instability cause the spirals.

Contribution

It provides the first near-infrared polarimetric observations of WaOph 6 and compares them with millimeter data, testing formation scenarios through simulations.

Findings

Spiral features are traced in both near-infrared and millimeter data.

Simulations suggest planetary perturbations could explain the observed spirals.

The study discusses the likelihood of gravitational instability versus planetary influence.

Abstract

[Full abstract in the paper] In recent years, protoplanetary disks with spiral structures have been detected in scattered light, millimeter continuum, and CO gas emission. The mechanisms causing these structures are still under debate. A popular scenario to drive the spiral arms is the one of a planet perturbing the material in the disk. However, if the disk is massive, gravitational instability is usually the favored explanation. Multiwavelength studies could be helpful to distinguish between the two scenarios. So far, only a handful of disks with spiral arms have been observed in both scattered light and millimeter continuum. We aim to perform an in-depth characterization of the protoplanetary disk morphology around WaOph 6 analyzing data obtained at different wavelengths, as well as to investigate the origin of the spiral features in the disk. We present the first near-infrared polarimetric observations of WaOph 6 obtained with SPHERE at the VLT and compare them to archival millimeter continuum ALMA observations. We traced the spiral features in both data sets and estimated the respective pitch angles. We discuss the different scenarios that can give rise to the spiral arms in WaOph 6. We tested the planetary perturber hypothesis by performing hydrodynamical and radiative transfer simulations to compare them with scattered light and millimeter continuum observations.