Lunch talk on Nov. 27, 2023

Unveiling the Formation of Giant Planets: Observational Modeling in the New Era of Exoplanet Discovery

Speaker:Yuhiko Aoyama (KIAA-PKU)

Venue:SWIFAR Building 2111

Time:12:30 PM, Monday, Nov. 27, 2023

Abstract:

The discovery of over 5000 exoplanets has unveiled a striking diversity in planetary systems, raising a pivotal question: how is such diversity achieved? A critical piece of this puzzle lies in understanding giant planets such as Jupiter, whose early formation and significant gravitational influence are crucial in shaping planetary systems. This research delves into the theoretical modeling of observable signatures of forming giant planets, focusing on two key aspects. Firstly, we explore the direct imaging of hot emissions from accreting giant planets. As these planets accrete gas from the protoplanetary disks, the released gravitational energy heats the gas, leading to observable hot emissions including atomic hydrogen lines. To analyze these emissions, we developed a comprehensive model that integrates the physics of accretion shock with thermodynamics, chemistry, and radiative transfer. This model proves instrumental in interpreting observational data and estimating the mass accretion rates and geometry of these forming planets. Secondly, we investigate the planet-induced observable substructures in protoplanetary disks, such as density gaps, spiral waves, and velocity anomalies. While these features have been traditionally studied in the context of viscous disks, recent findings suggest a dominance of Magneto-HydroDynamic (MHD) disk winds in the disk evolution. Our pioneering 3D non-ideal MHD simulations reveal that in these "windy disks," the density gaps around forming planets are deeper and wider, with velocity anomalies distinctly different from those in viscous disks. Finally, I will discuss the gas accretion from protoplanetary disks to the forming planets, bridging the two main aspects of my research. These works not only bridge the gap between theoretical and observational studies of forming giant planets but also contribute to our understanding of the evolution and population of exoplanets.