Though concentric rings — shown here in particularly beautiful clarity — are a common substructure among such discs, their widths, separations, and number can vary greatly. It’s still unclear how these substructures form, and how planets emerge from them. Quantifying and studying these similarities and differences was a motivator for constructing ALMA, and was the main objective of DSHARP. These details may hold clues to the type of planetary system that will eventually emerge.
Astronomers theorize that when our Sun was still young, it was surrounded by a disc of dust and gas from which the planets eventually formed. It is further theorized that the majority of stars in our Universe are initially surrounded in this way by a “protoplanetary disk“, and that in roughly 30% of cases, these disks will go on to become a planet or system of planets.
Sharp new observations have revealed striking features in planet-forming discs around young stars. The SPHERE instrument, mounted on ESO’s Very Large Telescope, has made it possible to observe the complex dynamics of young solar systems — including one seen developing in real-time. The recently published results from three teams of astronomers showcase SPHERE’s impressive capability to capture the way planets sculpt the discs that form them — exposing the complexities of the environment in which new worlds are formed.
The Atacama Large Millimeter/submillimeter Array (ALMA) has made the first ever resolved observation of a water snow line within a protoplanetary disc. This line marks where the temperature in the disc surrounding a young star drops sufficiently low for snow to form. A dramatic increase in the brightness of the young star V883 Orionis flash heated the inner portion of the disc, pushing the water snow line out to a far greater distance than is normal for a protostar, and making it possible to observe it for the first time. The results are published in the journal Nature on 14 July 2016.
This new image from the Atacama Large Millimeter/submillimeter Array (ALMA) shows the finest detail ever seen in the planet-forming disc around the nearby Sun-like star TW Hydrae. It reveals a tantalising gap at the same distance from the star as the Earth is from the Sun, which may mean that an infant version of our home planet, or possibly a more massive super-Earth, is beginning to form there.