Exoplanets and planet formation is a frontier interdisciplinary field in astronomy that explores the possibility of life in the universe and seeks to understand the origin of our own Solar System. It aims to answer two fundamental questions: How do planetary systems form from interstellar dust and gas? And do Earth-like planets suitable for life exist in our Galaxy? The Zhejiang University Institute of Astronomy has identified this as a key area for development. Led by Researcher Liu Beibei and Researcher Yang Haifeng, we have assembled a research team spanning the formation, evolution, and detection of planetary systems. The team is dedicated to systematically unraveling the birth and diversity of planetary worlds, from the initial conditions in protoplanetary disks to the final architectures of mature systems, by combining cutting-edge theory, high-performance numerical simulations, and multi-wavelength observations (especially in radio and optical bands).
1. Main Research Directions
Our research spans the entire journey of planetary systems from cradle to maturity, primarily covering the following two core areas:
1.1 Formation and Early Evolution of Planetary Systems
Led by Researcher Yang Haifeng, this direction focuses on the cradle of planets—the protoplanetary disk—and is dedicated to revealing the physical processes of dust growth, planetary embryo formation, and disk-planet interactions.
Dust Physics in Protoplanetary Disks: Pioneering the use of the unique probe of (sub)millimeter-wave dust self-scattering polarization to precisely measure the size distribution, spatial settling (scale height), and growth timescales of dust grains within protoplanetary disks. These observations provide critical constraints for understanding how planetary seeds (planetesimals) grow from micron-sized dust into kilometer-sized planetary embryos, directly testing classical planet formation theories.
Magnetic Fields and Dynamics in Protoplanetary Disks: Conducting in-depth research on the crucial role of magnetic fields in the structure, mass transport (accretion and disk winds), and evolution of protoplanetary disks. Innovatively proposing a novel method to detect surface magnetic fields using optical/near-infrared scattering polarization. Furthermore, studying how magnetically-driven disk winds influence disk size, evolutionary pathways, and internal material transport through non-ideal magnetohydrodynamic (MHD) simulations.
Disk Substructures and Environment: Using high-resolution ALMA polarization and intensity imaging to study substructures like rings, gaps, and spirals within protoplanetary disks. We investigate their dynamical interaction with forming planets and the impact of physical processes like turbulence on the planet-forming environment.
1.2 Exoplanet Detection, Characterization, and System Dynamics
Led by Researcher Liu Beibei, this direction focuses on the detection methods for mature planetary systems, the physical properties of planets, and their overall dynamical architecture.
Exoplanet Detection and Search: Utilizing various techniques such as the transit method (e.g., TESS mission), radial velocity method, and direct imaging to search for planets beyond our Solar System, particularly terrestrial planets and worlds located within the habitable zone.
Planetary Properties and Atmospheric Characterization: Analyzing transmission spectra (e.g., with JWST) to study the atmospheric composition, temperature structure, clouds, and potential biosignatures of exoplanets, advancing toward the ultimate goal of identifying another Earth.
Planetary System Dynamics and Stability: Researching the orbital configurations, resonance mechanisms, long-term dynamical evolution, and stability of multi-planet systems. We investigate how processes like planet-planet scattering and tidal interactions shape the diversity of systems we observe.
2. Research Methods and Distinctive Features
The team employs a trinity research paradigm integrating multi-wavelength observations, theoretical models, and high-performance numerical simulations, forming a complete research chain from microscopic physics to macroscopic systems.
Observational Aspects: Deeply participating in and leading high-resolution, multi-band (especially polarization) observations using the Atacama Large Millimeter/submillimeter Array (ALMA). Simultaneously, we utilize top-tier optical instruments like VLT/SPHERE and space telescopes such as TESS and JWST to achieve multi-dimensional, high-sensitivity detection of both protoplanetary disks and exoplanets.
Theoretical and Simulation Aspects: Developing and applying a series of advanced computational tools, ranging from microscopic radiative transfer simulations and dust growth models to macroscopic planet formation N-body simulations and magnetohydrodynamic (MHD) simulations. Relying on the institute's Galaxy high-performance heterogeneous computing platform, we achieve self-consistent simulations and theoretical predictions of complex physical processes.
Technological Innovation: The team has distinctive strengths in the theory and application of polarization observations. The dust self-scattering theory proposed by Researcher Yang Haifeng revolutionized the interpretation of ALMA polarization data and established it as a new standard tool for probing dust properties. His proposed optical/near-infrared polarization magnetometry technique opens a novel path to tackle the worldwide challenge of directly detecting magnetic fields in protoplanetary disks.
3. Scientific Goals and Significance
Through the research outlined above, we aim to:
Reveal the key physical processes and timescales of dust growth, settling, and planetesimal formation in protoplanetary disks, constructing a more complete theory of planet formation.
Achieve the first direct detection of magnetic fields in protoplanetary disks, clarifying their central role in driving disk evolution and shaping the planet-forming environment.
Discover and characterize new exoplanetary systems, particularly terrestrial planets, and conduct in-depth studies of their atmospheric physics and chemistry.
Understand the overall dynamical evolution laws of planetary systems, revealing the commonality and uniqueness of our Solar System within the Galaxy.
Cultivate innovative interdisciplinary talent skilled in processing massive observational datasets, developing frontier theoretical models, and running large-scale numerical simulations. This provides core scientific support for national strategic needs in areas like deep space exploration and the utilization of major scientific facilities.
The field of exoplanets and planet formation connects stellar physics, galactic chemical evolution, and even astrobiology. It stands at the scientific frontier addressing humanity's eternal question: Are we alone? The team in this direction at the Zhejiang University Institute of Astronomy is committed to achieving a series of breakthroughs in this exciting field, from cradle to home. We look forward to collaborating with peers worldwide to jointly unveil the mysteries of worlds beyond our Solar System.
