The morphology of CSCha circumbinary disk suggesting the existence of a Saturn-mass planet

TL;DR

This study uses high-resolution ALMA observations and hydrodynamic simulations to analyze the circumbinary disk of CS Cha, suggesting the possible presence of a Saturn-mass planet based on disk morphology.

Contribution

It provides the first detailed analysis of CS Cha's circumbinary disk morphology, proposing the existence of a Saturn-mass planet based on observational and simulation data.

Findings

Disk cavity resolved in dust continuum and CO emission

Disk is azimuthally axisymmetric with low eccentricity

Morphology consistent with a Saturn-like planet near the cavity edge

Abstract

Planets have been detected in circumbinary orbits in several different systems, despite the additional challenges faced during their formation in such an environment. We investigate the possibility of planetary formation in the spectroscopic binary CS Cha by analyzing its circumbinary disk. The system was studied with high angular resolution ALMA observations at 0.87mm. Visibilities modeling and Keplerian fitting are used to constrain the physical properties of CS Cha, and the observations were compared to hydrodynamic simulations. Our observations are able to resolve the disk cavity in the dust continuum emission and the 12CO J:3-2 transition. We find the dust continuum disk to be azimuthally axisymmetric (less than 9% of intensity variation along the ring) and of low eccentricity (of 0.039 at the peak brightness of the ring). Under certain conditions, low eccentricities can be achieved in simulated disks without the need of a planet, however, the combination of low eccentricity and axisymmetry is consistent with the presence of a Saturn-like planet orbiting near the edge of the cavity.