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Full-Text Articles in Physical Sciences and Mathematics
Constraining Protoplanetary Disc Accretion And Young Planets Using Alma Kinematic Observations, Ian Rabago, Zhaohuan Zhu
Constraining Protoplanetary Disc Accretion And Young Planets Using Alma Kinematic Observations, Ian Rabago, Zhaohuan Zhu
Physics & Astronomy Faculty Research
Recent ALMA molecular line observations have revealed 3D gas velocity structure in protoplanetary discs, shedding light on mechanisms of disc accretion and structure formation. (1) By carrying out viscous simulations, we confirm that the disc's velocity structure differs dramatically using vertical stress profiles from different accretion mechanisms. Thus, kinematic observations tracing flows at different disc heights can potentially distinguish different accretion mechanisms. On the other hand, the disc surface density evolution is mostly determined by the vertically integrated stress. The sharp disc outer edge constrained by recent kinematic observations can be caused by a radially varying alpha in the disc. …
Kozai–Lidov Oscillations Triggered By A Tilt Instability Of Detached Circumplanetary Discs, Rebecca G. Martin, Zhaohuan Zhu, Philip J. Armitage, Chao-Chin Yang, Hans Baehr
Kozai–Lidov Oscillations Triggered By A Tilt Instability Of Detached Circumplanetary Discs, Rebecca G. Martin, Zhaohuan Zhu, Philip J. Armitage, Chao-Chin Yang, Hans Baehr
Physics & Astronomy Faculty Research
Circumplanetary discs can be linearly unstable to the growth of disc tilt in the tidal potential of the star–planet system. We use 3D hydrodynamical simulations to characterize the disc conditions needed for instability, together with its long-term evolution. Tilt growth occurs for disc aspect ratios, evaluated near the disc outer edge, of H/r ≳ 0.05, with a weak dependence on viscosity in the wave-like regime of warp propagation. Lower mass giant planets are more likely to have circumplanetary discs that satisfy the conditions for instability. We show that the tilt instability can excite the inclination to above the threshold where …