CAREER: The Formation and Disruption of Resonant Chains

About This Grant

Within our Galaxy, planets form close-in (closer than the distance from the Sun to the Earth), multiple (sets of two or more), and low-mass (up to several Earth masses, as opposed to giant planets) around roughly 30% of stars like the Sun. It is possible that the majority of these types of planetary systems formed with orbital periods in sync with each other, and that these resonant chains settled at the inner edges of planet-forming gas disks. After the gas disk dissipates, these resonances could gradually be disrupted due to the growth of eccentricity and inclination, leading to collisions. This award combines cutting-edge observations, novel data analysis techniques, and rigorous numerical simulations to address the missing links in this emergent paradigm of planet formation. Broader impact in the state of Hawaii will be training programs for high-school through graduate students in scientific computing and other research tasks and education and public outreach to the local community. Data from ground-based telescopes in Hawaii and elsewhere will acquire new transit times and radial velocities to complement the space-based discovery and atmospheric characterization data for resonant chains. N-body simulations will be used to model the photometry, assess stability, and track planet formation including giant impacts. The state of resonant libration or circulation and the role of second-order and non-adjacent resonances in disrupting chains will be assessed. Whether the prominent radius gap separating super-Earths and mini-Neptunes could be populated by giant impact collisions during the disruption of resonant chains will be determined. Atmospheric studies of resonant-chain planets will measure their atmospheric CO ratio and metallicity. It appears the terrestrial planets of the Solar System did not form a resonant chain initially; Jupiter and Saturn’s presence may have prevented that, so new radial velocity data will be acquired to test whether their analogs are present around resonant-chain systems. The Intro2Astro summer workshop, which teaches the basics of astronomy research skills to early-career and undergraduate students, will be enhanced with in-person sessions at the University of Hawaii and a new module on how to apply to REU programs. The Mauna Kea Scholars—high school students participating in research—will author telescope proposals and perform data analysis. To integrate the key concepts and discoveries of this research into educational activities, a planet orrery will be added to the department’s StarLab outreach events. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.