How did our solar system’s planets first form within the swirling disk of gas and dust that surrounded the newborn Sun? One of the best ways to answer this question is watch other solar systems as they form — and the Atacama Large Millimeter/submillimeter Array (ALMA) continues to help us do so.
A History of Large Targets
Gallery of 240 GHz (1.25 mm) continuum emission images for the disks in the DSHARP sample. The scale bars in the lower right of each image indicate 10 au. Click to enlarge. [Andrews et al. 2018]When ALMA revealed early observations of the disks of gas and dust around young stars, we were stunned by the exquisitely detailed look this interferometer provided into newborn solar systems. Since then, again and again, ALMA has produced remarkable images of gaps, rings, and spiral arms in disks, all of which hint at how planets might be forming.
Thus far, however, we’ve mostly focused on imaging the especially large disks that give us the best look at disk substructure. As an example, the Disk Substructures at High Angular Resolution Project (DSHARP) survey used ALMA to image twenty large, bright disks with effective radii — the radius that encompasses ...