Observational Signatures of Dust Traffic Jams in Polar-Aligning Circumbinary Disks

TL;DR

This paper uses hydrodynamical simulations to show how dust traffic jams form in misaligned circumbinary disks during polar alignment, producing observable rings at cm wavelengths.

Contribution

It demonstrates the formation of dust traffic jams due to differential precession in misaligned disks and predicts their observational signatures with upcoming telescopes.

Findings

Multiple dust traffic jams form during polar alignment.

Distinct rings in continuum images correspond to traffic jams.

Upcoming telescopes can resolve these features in protoplanetary disks.

Abstract

Misaligned circumbinary disks will produce dust traffic jams during alignment or anti-alignment to the binary orbital plane. We conduct a hydrodynamical simulation of an initially misaligned circumbinary disk undergoing polar alignment with multiple dust species. Due to differential precession between the gas and dust components, multiple dust traffic jams are produced within the disk during polar alignment. The radial locations of the dust traffic jams depend on the Stokes number of the grains, which depends on grain size. We compute the dust temperature structure using post-processing radiative transfer to produce continuum images at cm-wavelengths. Multiple distinct rings emerge in the continuum images, corresponding to the dust traffic jams. The angular resolution of upcoming observations from SKA and ngVLA will be sufficient to detect centimeter-sized grains in protoplanetary disks and resolve the widths of dust traffic jams. Therefore, dust traffic jams resulting from the differential precession of gas and dust in misaligned circumbinary disks will be a prime target for more extended wavelength observations.