Exploring Planetary System Evolution Through High-Contrast Imaging
- Author(s): Esposito, Thomas Matthew
- Advisor(s): Fitzgerald, Michael P
- et al.
High-contrast imaging of circumstellar debris disks and exoplanets provides unique information about planetary system evolution. Several hundred nearby main-sequence stars are known to host debris disks: reservoirs of rock and ice that are thought to be coeval with planet formation. My dissertation research focused on detecting and characterizing such disks to gain new insight into circumstellar environments during the epoch of planet assembly. To view these systems on spatial scales down to a few astronomical units, I used near-infrared angular differential imaging data from the Keck NIRC2 and Gemini Planet Imager instruments. Detection of relatively faint disks and planets in these data is enhanced by image-processing algorithms that suppress the stellar signal, however, they also bias the brightnesses of these objects. I developed a new technique to forward-model and correct for this bias, thus allowing more accurate analysis of disk and planet properties. Applying this technique to scattered-light imaging of the HD 32297 debris disk, I used photometric and morphological measurements to infer physical characteristics of the disk and its constituent grains. I also investigated the HD 61005 debris disk and the role that an eccentric, inclined planet could play in shaping its unusual morphology. To expand the small samples of resolved disks and directly-imaged planets, I conducted a coronagraphic survey of 24 nearby stars, the preliminary results of which are reported herein. Concluding on the same theme of high-angular resolution imaging, my final project comprised tasks translating science requirements into design specifications for an upgraded Keck OSIRIS imager.