I'm an observational astronomer with an interest in planet formation. I use interferometric imaging techniques to push the capabilities of adaptive optics corrected telescopes. I've mostly been using non-redundant masking to search for and characterize companions in transition disks (protoplanetary disks with inner clearings that might be shaped by forming planets).
Comparing Non-Redundant Masking and Filled-Aperture Kernel Phase
I used real data and simulations to compare the techniques of non-redundant masking (NRM) and filled-aperture kernel phase for exoplanet detection. While NRM uses a mask to turn a conventional telescope into a non-redundant interferometer with several sub-apertures, kernel phase involves treating a conventional telescope as if it were made up of many sub-apertures with redundant baselines. We found that under certain conditions, kernel phase can outperform NRM. Both techniques will produce exciting results on the next generation of telescopes and AO systems. Check out the article on arXiv and soon in JATIS.
LkCa 15: Multiple Planets in Formation
Large Binocular Telescope and Magellan Adaptive Optics System observations of the LkCa 15 revealed the first unambiguous direct images of planet formation! The position evolution of three infrared sources in the disk clearing allow for distinct circular orbits aligned with the outer disk. We also detect H-alpha emission coming from one of the sources, tracing accretion directly! The infrared fluxes, apparent orbital motion, and H-alpha emission are best explained by three planets with circumplanetary accretion disks. Check out the paper on the arXiv, in Nature, or in the news.
The T Cha transition disk had a protoplanet candidate detected in a single epoch observation. Here I took a look at several epochs of Very Large Telescope and Magellan Adaptive Optics System observations of T Cha. The images and best companion model fits can't be explained by a planet orbiting in the plane of the outer disk. Check out the paper on the arXiv or in The Astrophysical Journal.
Forward Scattering Simulations
Transition disks are dusty! And masking observations aren't always the best at telling the difference between signals caused by scattered light from disk material and protoplanet companions. Here I compare the multi-epoch datasets we have for T Cha and LkCa 15. I simulate NRM observations of T Cha's outer disk and LkCa 15's inner and outer disks. I show that the companion signal in T Cha is best explained by forward scattering from the outer disk. However, the two LkCa 15 disks can't cause companion signals with positions that change smoothly over time. Check out the paper on the arXiv or on SPIE.