Geoffrey Bryden
Staff Scientist
Jet Propulsion Lab
Related papers
Multiple Planets
Above picture: Postscript
Above picture: full-screen GIF format
Above picture: TIFF format
Above picture: PPM format
This computer rendering is based on a hydrodynamic model which calculates the evolution of a protostellar disk as a giant protoplanet forms. In particular, the model follows the interaction between the planet and the disk. With the newly formed protostar in the center of the disk, a Jupiter-mass protoplanet forms at Jupiter's distance to the Sun (seen as a small red sphere). The protoplanet excites density waves in the gas which propagate away from the protoplanet. These waves, which push the gas away from the protoplanet and are responsible for the planet's orbital migration, are easily visible in the plot as spiral patterns. (In the plot, both color and "height" are used to show the disk surface density - high red bumps indicate high surface density, green is the original, unperturbed density, and blue is low surface density.) Because the disk has a certain amount of prescribed viscosity, the waves are damped out as they ripple away from the planet; if a lower viscosity were used the waves would travel farther and the spiral pattern would continue out toward the disk edge. Most importantly, the gas-protoplanet interaction clears out a gap in the disk. Once this gap forms, there is no longer any gas left to accrete onto the protoplanet, and it stops growing. In this particular model the surface density in the gap is less than a millionth of its original value.
Geoffrey Bryden
Jet Propulsion Lab
MS 169-506
4800 Oak Grove Drive
Pasadena, CA 91109
e-mail to Geoffrey.Bryden at jpl.nasa.gov