Among solar-type main sequence stars with FGK spectral types, exoplanets and debris disks are fairly common. Gas (Ice) giants like Jupiter (Neptune) orbit roughly 20% (early 100%) of these stars. Although warm dust in orbits similar to Venus, Earth, and Mars are quite rare, 20% t0 30% of solar-type stars have cold dust in orbits at 20 au to 30 au (like those of Uranus and Neptune) out to 200 au.

Working with Ben Bromley (Univ of Utah) and Joan Najita (NOIRLab), I try to unerstand the formation and evolution of these planetary systems. We use analytical and numerical calculations to develop predictions that can be compared with observations.

For numerical simulations, Ben and I built Orchestra, a C++ code which follows the evolution of a disk of gas and dust as it evolves into a planetary system.

Our recent projects include:

  • During the formation of terrestrial planets, Moon-sized to Mars-sized protoplanets collide and merge into larger and larger protoplanets. These giant impacts should also produce a warm debris disk, but these are rarely observed. We study ways to avoid this debris signature of terrestrial planet formation.
  • At larger distances, debris disks are common. We showed that ensembles of planetesimals and pebbles evolve into debris disks with properties similar to those observed.
  • A decade ago, we used a set of Orchestra calculations to demonstrate that gas giants with masses similar to Jupiter grow within disks of pebbles and planetesimals. We are hoping to return to these kinds of calculations in the future to see whether there are obswervable features of this evolution.
Photo credit: Jeff Dunas