Science Highlight

The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) is the first ALMA Large Program dedicated to debris discs. The 24 most most promising belts were observed and imaged. Using parametric and non-parametric models, the radial and vertical distribution of dust (amber images in the figure) were constrained, as well as the presence of asymmetries. For a subset of six belts with CO gas (blue images in the figure), the gas distribution and kinematics was constrained as well. Up to a third of the sample exhibits substructures in the form of multiple dusty rings that may have been inherited from their protoplanetary discs. For highly inclined belts, it was found that non-Gaussian vertical distributions are common and could be indicative of multiple dynamical populations. 10 of the 24 belts present asymmetries in the form of density enhancements, eccentricities, or warps. The CO gas is radially broader than the dust, but this could be an effect of optical depth. At least one system shows non-Keplerian kinematics due to strong pressure gradients, which may have triggered a vortex that trapped dust in an arc. Finally, evidence was found that the micron-sized grains may be affected by gas drag in gas-rich systems, pushing the small grains to wider orbits than the large grains. A link to the main publication (with references to further papers therein) is here.