Planet formation in the α Centauri and Kepler 16-b systems
Using a new code I developed, I am studying the conditions for planet formation in a number of observed binary systems, including α Centauri (planets in a circumstellar configuration around either A or B) and Kepler 16-b (planets in circumbinary configurations). α Centauri is an excellent candidate for terrestrial planet searches, and the binary configuration allows for stable orbits in the habitable zone. Kepler 16-b is the first planet to be discovered in a circumbinary configuration. Both systems will represent a unique testing ground connecting the outcome of planet formation theories to observations. A theoretical understanding of the pathways to planet formation in a disturbed environment (vs. unperturbed planet formation around single stars) will prove essential in determining the prevalence of terrestrial planets in multiple stellar systems, and constraining the likelihood of their detection by the ongoing RV and transit searches.
I am conducting simulations of protoplanetary disks with embedded planetesimals around binaries using a new Smoothed Particle Hydrodynamics (SPH) code. The mutual impact speeds and orbital elements of the planetesimals determine the conditions for the formation of planetary embryos, and interact in a non-trivial way with the gas disk and the stellar companion’s gravity.
Detection of exoplanets: radial velocity
I am a member of the Lick-Carnegie RV survey. We use HIRES to obtain precise radial velocities at the Keck observatory. Planets I helped identify span from a few Earth masses to several Jupiter masses.
Detection of exoplanets: transit timing
More than 100 planets have been discovered in transit over their parent star. When precise timings of their transits are obtained, small deviations from strict periodicity can pinpoint the presence of additional bodies in the system. I examined synthetic datasets combining transit timing and radial velocities as generated by a number of orbital configurations. The analysis showed that degeneracies in the solution may preclude the correct identification of the additional bodies, unless good RV coverage is undertaken as well.
Groove instabilities in protoplanetary disks
Density gaps in protoplanetary disks can cause an otherwise stable disk to go wildly unstable. I showed the emergence of these groove modes in self-gravitating protoplanetary disks using a generalized eigenvalue code, and confirmed them with hydrodynamical simulations.
The Systemic Console
The Systemic Console is used around the world by research groups and classrooms to analyze radial velocity datasets and derive the orbital properties of putative planetary systems. It includes a large array of tools for error estimation, orbital stability, plotting and animation.
Credit for Kepler 16-b image: NASA/JPL-Caltech/T. Pyle