HD 143006: circumbinary planet or misaligned disc?

TL;DR

This study uses hydrodynamic simulations to explain the complex disc features around HD 143006, suggesting the presence of a misaligned circumbinary planet and a strongly inclined binary system, which could be the first of its kind.

Contribution

The paper introduces a comprehensive model combining a strongly inclined binary and an outer planetary companion to explain observed disc asymmetries and shadows in HD 143006.

Findings

Successfully reproduces observed shadows and brightness asymmetry.

Identifies a 10 Jupiter mass planet influencing dust distribution.

Predicts observable changes in shadows and kinematics over 5-10 years.

Abstract

Misalignments within protoplanetary discs are now commonly observed, and features such as shadows in scattered light images indicate departure from a co-planar geometry. VLT/SPHERE observations of the disc around HD 143006 show a large-scale asymmetry, and two narrow dark lanes which are indicative of shadowing. ALMA observations also reveal the presence of rings and gaps in the disc, along with a bright arc at large radii. We present new hydrodynamic simulations of HD 143006, and show that a configuration with both a strongly inclined binary and an outer planetary companion is the most plausible to explain the observed morphological features. We compute synthetic observations from our simulations, and successfully reproduce both the narrow shadows and the brightness asymmetry seen in IR scattered light. Additionally, we reproduce the large dust observed in the mm continuum, due to a 10 Jupiter mass planet detected in the CO kinematics. Our simulations also show the formation of a circumplanetary disc, which is misaligned with respect to the outer disc. The narrow shadows cast by the inner disc and the planet-induced "kink" in the disc kinematics are both expected to move on a time-scale of $\sim$ 5-10 years, presenting a potentially observable test of our model. If confirmed, HD 143006 would be the first known example of a circumbinary planet on a strongly misaligned orbit.