Peering at the First Stages of Planet Formation: Getting a Clearer View of Grain Growth, Settling, and Clearing in Dusty Disks

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Dr. Catherine Espaillat is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the Harvard-Smithsonian Center for Astrophysics. Dr. Espaillat will quantify dust evolution in protoplanetary disks around low-mass pre-main sequence stars, the precursors of our own Sun. To this end the PI will measure grain growth and settling, the first two steps towards planet formation, in disks located within the star-forming clouds of Taurus, Chamaeleon, and Ophiuchus. In addition to studying "full" disks the PI will also target objects which are in the process of clearing gaps in their disks, a phenomena which is most likely due to newly formed planets. The main tool in exploring these issues will be the state-of-the-art D'Alessio disk model, which the PI will advance to the next level of sophistication in this proposed study. By combining spectral energy distributions that employ mid-infrared Spitzer and far-infrared Herschel data with spatial brightness distributions obtained with interferometers in the millimeter and infrared, the PI will provide a self-consistent analysis of the amount of dust growth, settling, and clearing in disks, which will also serve as a guide for future disk studies with the James Webb Space Telescope (JWST). The systematic, semi-empirical evidence obtained throughout this project will provide needed insight and constraints to aid in theoretical modeling of dust evolution and planet formation, bringing us a few steps closer to understanding the origin of our own solar system.Dr. Espaillat will also develop a formal mentor-training program with the Harvard College Science Mentors Program and will establish a similar university mentoring program for minority students in science. Through these two programs the PI will train graduate students who have volunteered to serve as mentors to younger women and minority graduate and undergraduate students.