Dr. Eugene Chiang of the University of California (Berkeley) will undertake a three year study of the various forces that affect the growth and destruction of dust and small bodies in circumstellar debris disks. These forces include collisions, stellar radiation, and the gravitational perturbation from planets. The work will also elucidate how early planets and destructive collisions scatter or eliminate dust from the debris disks. The main goal will be to infer the masses and orbits responsible for the variety of structures seen in high-resolution images of these disks.
The project will address many issues about the formation of the Kuiper Belt of dust and cometary bodies in our own solar system and may be useful for the interpretation of future observations, like those from the NSF-supported Gemini Planet Imager survey. The principal investigator and his group also plan a number of public outreach activities to illustrate the processes of planet formation.
Thanks to this NSF grant, we (1) solved the puzzle of how km-sized moonlets embedded in Saturn's rings migrate: they do so stochastically, buffeted by gravitational interactions with decameter-sized boulders; (2) established a new criterion for how particles achieve gravitational instability to form planetesimals when aerodynamically well-coupled to gas; (3) mapped in unprecedented detail the parent-body birth rings orbiting Vega and AU Mic; (4) proposed a new explanation for the enormous concentrations of dust observed by the Atacama Large Millimeter Array: these dust particles concentrate by aerodynamic drag within large-scale gas overdensities mainted by disk self-gravity; and (5) developed both empirical and analytic scaling relations for the depths of gaps cleared by giants planets within circumstellar disks. The broader impacts of this work were that we mentored and advanced the careers of many graduate students and postdocs, including (1) Dr. Meredith Hughes, who is now a tenure-track facuty member at Wesleyan University; (2) Dr. Ji-Ming Shi, who secured a second postdoctoral fellowship at Princeton University; (3) Mr. Jeffrey Fung, who was awarded an NSERC Postdoctoral Fellowship and is planning to take it to Berkeley; (4) Ms. Katherine Rosenfeld, who will obtain her PhD at Harvard next year; (5) Mr. Tushar Mittal, a beginning graduate student at Berkeley who thanks to our work on dust concentrations is now prepared to take his Qualifying Exam this coming Spring; and (6) Dr. Margaret Pan, who leveraged her work on collisional cascades and moonlet-disk interactions to secure new multi-year grants from the National Science Foundation and NASA.
