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Image courtesy of Ruobing Dong

Computer Simulations Shed Light on the Birth of Planets

Planets form in protoplanetary disks, which are gaseous and dusty circumstellar disks surrounding newborn stars. In these systems, the forming planets gravitationally interact with the disk, and create structures. One type of such structures is annular gaps opened by planets, which has been identified in resolved observations of a few disks, such as HL Tau and TW Hya. However, in each of these two systems, there are a pair of gaps that appear to be too narrow and too close to each other to be explained by conventional methods of gap opening by planets. With collaborators, Steward Bok Fellow Ruobing Dong proposes that these structures can be explained by a special type of gap opening caused by low mass planets in a low viscosity environment. Conventional models usually invoke relatively massive planets, such as Saturn and Jupiter, to explain observed gaps in disks; in contrast, the new model makes use of super-Earths, planets with sizes in between the Earth and Neptune. Such planets are the most abundant among discovered planets to date, yet their formation mechanism is still an open question. The new proposal establishes a critical link between super-Earth formation events and detectable structures in disks. The left panel of the figure (above) shows the spatial distribution of dust grains in a disk model with a 10 Earth mass planet, and the right panel is the corresponding synthetic image of system as if observed by ALMA. You can see the UA press release HERE. The Arizona Daily Star article is HERE.