单个迁移行星在原行星盘中形成多个尘埃环与间隙：局地等温盘的参数研究
Formation of multiple dust rings and gaps in protoplanetary discs by a single migrating planet. A parameter study in locally isothermal discs
AI总结：
本研究通过FargoCPT代码模拟局地等温盘，发现迁移行星在α≤10⁻⁴时可形成延伸至r~150 au的长寿多环结构，解释原行星盘多环的行星起源机制。
AI中文摘要：
ALMA观测显示，大型原行星盘通常包含多个同心尘埃环，被黑暗间隙分隔。一个自然的解释是尘埃在新形成行星打开的间隙边缘被捕获，但行星通常在短于盘寿命的时标内向内迁移，这似乎与大半径处存在环的观测结果矛盾。本研究旨在探究迁移行星能在r~150 au处形成长寿多环结构的条件，以约束环的行星起源假说的参数空间。我们使用FargoCPT流体动力学代码，运行二维局地等温盘模型，包含单个迁移行星，改变盘的纵横比、黏度（α）和行星质量。在所有模型中，行星最终在深间隙中停滞。当α≤10⁻⁴时，行星引发的次级螺旋可在更小半径处打开额外间隙；当行星在停滞前质量超过当地热质量的两倍时，会进入交替缓慢迁移与III型快速迁移的 regime，在其轨道外留下部分间隙。间隙边缘始终存在压力极大值，可捕获尘埃；这些压力极大值在α≤10⁻⁴时最初为大涡旋，但逐渐弥散成环后消散。III型迁移遗留的环在α=10⁻³时消散迅速，而在α≤10⁻⁴时至少持续300-500 kyr，弥散或消散时标随α降低而增加。我们的结果表明，迁移行星可通过其停滞（r≤50 au）、次级间隙打开（r≤20 au）及III型迁移遗留物（在足够大质量盘中的木星质量行星可延伸至r~150 au），重现观测到的盘多环结构。需开展更长时间的模拟，以将环与涡旋出现的统计结果与观测进行比较。
英文摘要：
ALMA observations show that large protoplanetary discs usually contain multiple concentric dust rings separated by dark gaps. A natural explanation is dust-trapping at the edges of gaps opened by newly formed planets. However, planets typically migrate inward on timescales shorter than disc lifetimes, seemingly at odds with rings at large radii. We aim to investigate the conditions under which migrating planets can form long-lived, multi-ringed structures out to $r\sim 150$ au to constrain the parameter space for the planetary origin hypothesis of rings. Using the FargoCPT hydrodynamics code, we ran two-dimensional, locally isothermal disc models with a single migrating planet, varying disc aspect ratio, viscosity ($α$), and planetary mass. In all models, the planet eventually stalls in a deep gap. At $α\leq 10^{-4}$, secondary spirals launched by the planet can open additional gaps at smaller radii. When planets exceed twice the local thermal mass before stalling, they enter a regime of alternating slow and type-III rapid migration, leaving partial gaps outside their orbit. The gap edges consistently feature pressure maxima that trap dust. These begin as large vortices at $α\leq 10^{-4}$, but gradually smear out into rings before dissipating. The type-III remnant rings dissipate quickly at $α=10^{-3}$, but persist for at least 300-500 kyr at $α\leq 10^{-4}$. Both smear-out and dissipation timescales increase with lower $α$. Our results show that migrating planets can reproduce observed multi-ringed structures in discs with $α\lesssim 10^{-4}$ through their stall ($r\lesssim 50$ au), secondary gap-opening ($r\lesssim 20$ au), and type-III migration remnants (extending to $r\sim 150$ au for Jupiter-mass planets in sufficiently massive discs). Longer simulations will be required to compare the statistics of ring-to-vortex occurrence to observations.
