Speaker
Description
Stellar flybys are a common dynamical process in young stellar clusters and can significantly reshape protoplanetary discs. However, their impact on dust dynamics remains poorly understood, particularly in the weakly coupled regime ($\mathrm{St}≫1$). We present three-dimensional hydrodynamical simulations of parabolic stellar flybys—both coplanar and inclined—interacting with a gaseous and dusty protoplanetary disc. Gas and dust spirals differ in morphology and position, with their offset enhancing dust accumulation measured through the linear growth of the streaming instability. Flybys with mass equal to the central star (1 ${\rm M_{\odot}}$) truncate the disc, producing tightly wound, ring-like spirals that promote dust concentration. By mapping the streaming instability growth rates in the solid abundance-Stokes number space across three evolutionary phases, we find that a low-mass flyby suppresses dust concentration below the critical clumping threshold after periastron and maintains this suppression over time, indicating long-lasting inhibition of dust clumping. An equal-mass flyby raises growth rates well above the threshold, suggesting that such encounters may foster conditions favourable for dust clumping. Flyby-induced spirals play a central role in shaping dust evolution, leading to distinct spatial and temporal behaviours in weakly coupled discs.
| Participate the oral/poster presentation award competition | Yes |
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