Format: The movies on this page are encoded with a variety of codecs, including MPEG, DivX 3/4/5, and MPEG4. You may need to download video codecs for your media player in order to view these movies. On Linux, mplayer or Xine should play these out-of-the-box. On Windows, the DivX site may provide the needed codec. On Mac OS X, Quicktime may or may not be able to play these, or you can download MPlayer OS X.
Gap Formation: In this movie, a planet carves a gap in a gas disk.
The planet is initially 1 Jupiter-mass on a circular orbit at 12.5 AU in a 0.08 Solar-mass disk.
It migrates and accretes, forming a deep gap in just a few hundred years.
Once the gap has formed, the planet ceases migration, but continues to accrete gas from the edges of the gap.
The color represents the log of the gas density.
MPEG4 800x800 5.3M
Triggered Planet Formation: In this movie, a planet triggers the formation of an additional planet via the gravitational instability.
The planet is initially 2 Jupiter-masses on a circular orbit at 12.5 AU in a 0.09 Solar-mass disk.
The planet excites spiral density waves.
After a time, one of these waves produces a density perturbation strong enough that it collapses, forming a gravitationally bound object: another planet.
The color represents the log of the gas density.
MPEG4 800x800 5.3M
Here is another triggered formation scenario.
In this simulation the planet's mass is initially 1.5 Jupiter-masses, and the disk mass is 0.1 Solar-masses.
This time, more than one additional planet is formed.
Look for the mergers between planets.
MPEG4 800x800 4.1M
Exploding Planets: A Cautionary Tale: In this movie of an unstable disk simulation, two planets collide and explode, particles being sent off at super-luminal speeds.
The explosion is a numeric effect, due to a lower limit on the timesteps the particles are integrated on.
As the planets collide and merge, the multi-stepping scheme places the particles on the highest rung (smallest timestep) we allow.
We had arbitrarily limited the number of rungs (division by powers of 2) in the timestepping scheme, and the merging particles had bottomed out.
This causes them to move right next to and through each other in a single timestep.
When they suddenly find themselves arbitrarily close to one another, the force calculation blows up, giving them ridiculously high accelerations.
In the next timestep they acquire what is, in the simulation, super-luminal velocities, and the merger appears to explode.
We fixed this problem by allowing an effectively infinite number of rungs in the multi-stepping scheme.
The movie shows two views of the entire disk, a closeup of the explosion, and finally a closeup of the fixed situation.
MPEG4 600x600 2.2M
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