Understanding the remarkable diversity of planetary systems revealed in particular by the kepler mission is a central goal of modern astrophysics. To shed a new light on this fundamental question, the…

The National Aeronautics and Space Administration (NASA) awarded a $389,969.67 grant to the Regents of the University of California, doing business as the University of California, Berkeley (UC Berkeley), for a research project titled "Understanding the Remarkable Diversity of Planetary Systems Revealed in Particular by the Kepler Mission." The project aims to assess the diversity of structural properties among protoplanetary disks and the processes that drive disk evolution, such as vertical settling, radial migration, and dust-gas decoupling. This will be accomplished through high-resolution multi-wavelength imaging of edge-on protoplanetary disks, combined with advanced radiative transfer modeling. The project supports NASA's exoplanet research program and will help prepare for future observations with the James Webb Space Telescope (JWST). The grant does not have a set-aside designation and is scheduled for completion on July 25, 2023. UC Berkeley, as the prime contractor, will be administering the funding through the State of California Controller's Office.

Understanding the remarkable diversity of planetary systems revealed in particular by the kepler mission is a central goal of modern astrophysics. To shed a new light on this fundamental question, the core objective of this project is to assess the true diversity of structural properties among protoplanetary disks. Specifically, we aim at evaluating the degree to which processes such as vertical settling, radial migration and dust-gas decoupling, all believed to be key initial steps towards planet formation, are common in circumstellar disks, and to determine the role they play in disk evolution. To circumvent the highly ambiguous nature of spatially unresolved observations, a disk s structure must be probed through high-resolution imaging over a broad range of wavelengths, from visible scattered light images to radio wavelength thermal emission mapping. Disks that are fortuitously oriented so that we view them nearly edge-on provide a natural occulter to the glare of the central star, enabling studies that are daunting if not outright impossible for disks seen at lower inclinations. In particular, the disk s vertical structure is in full display in this case, and the presence of tenuous amounts of material at large distances from the central star is readily revealed thanks to the natural effect of line-of-sight integration. Our project, which builds on the legacy of several spitzer and herschel surveys to identify candidate edge-on disks in the first place, combines high-resolution imaging with HST, adaptive optics and sub-millimeter interferometric observations with state-of-the-art radiative transfer modeling. With over three dozen edge-on disks around solar-type and low-mass STARS already imaged with HST and/or ground-based adaptive optics as well as ongoing alma programs to map a large subset in both sub-millimeter dust continuum and molecular emission maps, we are in an ideal position to perform highly uniform modeling studies, enabling both object-to-object comparisons and a full characterization of the overall demographics of protoplanetary disks. This thorough panchromatic modeling will allow US to assess the intrinsic diversity of disk structure on a sound statistical basis and to draw comparisons with the statistical properties of planetary systems. In addition, we will make predictions for future high-resolution mid-infrared jwst observations that will bridge the GAP that exists between existing capabilities by probing deeper into these disks. Understanding the planet formation process through studies of protoplanetary disks, and explaining the diversity of planetary systems that emerge from IT, is directly relevant to NASA s exoplanet research program. Furthermore, this project builds on observations with previous and ongoing space mission led by, or with strong contribution from, NASA and will help prepare the planning and interpretation of future observations of protoplanetary disks with jwst. Finally, by directly involving two UC berkeley undergraduate students, this project will provide exciting opportunities for students to get engaged in research in a stem field.