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arXiv 2009.07575astro-ph.EP
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行星驱动螺旋中的尘埃动力学

Dust dynamics in planet-driven spirals

Ardjan Sturm, Giovanni Rosotti, Carsten Dominik

摘要:

上下文已知原行星盘具有螺旋特征,这些特征在散射光、ALMA连续谱以及最近的CO气体排放和气体动力学中被观察到。然而,尚不清楚气体和尘埃中的螺旋是否具有相同的形态。目标。我们研究了尘埃螺旋的形态和振幅作为斯托克斯数的函数,以及导致与气体螺旋不同的潜在机制。然后,我们构建了一个模型,将气体中开普勒旋转的偏差与气体和尘埃表面密度的扰动联系起来。方法.我们使用FARGO-3D与灰尘的实施,数值研究的螺旋,之后,使用半分析模型解释的结果。用观测资料对该模型进行了检验,并根据连续资料预测了气体动力学中的螺旋扰动。结果我们发现,螺旋的螺距角并没有显着不同的气体和尘埃。尘埃螺旋的振幅随斯托克斯数(St)而减小,并在典型的St > 0.1时开始淡出,因为尘埃与气体解耦。半解析模型提供了一个准确和快速的代表性的螺旋表面密度的灰尘从气体。我们在TW Hya速度残差图中发现了一个螺旋,这是以前从未见过的,这是垂直速度的一个特征,并且在连续间隙处有一个扭结,这为99 au的行星提供了强有力的证据。结论.我们建立了一个模型,给出了一个螺旋尘埃的基本动力学的估计,这可以作为螺旋的行星起源的证明,可以是一个探测盘中的斯托克斯数。

英文摘要:

Context. Protoplanetary disks are known to host spiral features that are observed in scattered light, ALMA continuum and more recently in CO gas emission and gas dynamics. It is however unknown if spirals in gas and dust trace the same morphology. Aims. We study the morphology and amplitude of dusty spirals as function of Stokes number and the underlying mechanisms causing a difference from gas spirals. We then construct a model to relate the deviation from Keplerian rotation in the gas to a perturbation in surface density of gas and dust. Methods. We use FARGO-3D with dust implementation to numerically study the spirals, after which the results are interpreted using a semi-analytical model. This model is tested on observational data to predict the perturbation of the spiral in gas dynamics based on the continuum data. Results. We find that the pitch angle of a spiral does not differ significantly between gas and dust. The amplitude of the dust spiral decreases with Stokes number (St) and starts to fade out at a typical St > 0.1 as the dust becomes decoupled from the gas. The semianalytical model provides an accurate and fast representation of the spiral in surface density of the dust from the gas. We find a spiral in the TW Hya velocity residual map, never seen before, which is a feature in the vertical velocity and has a kink at the continuum gap, yielding strong evidence for a planet at 99 au. Conclusions. We built a model that gives an estimate of the underlying dynamics of dust in a spiral, which can serve as a proof of planetary origin of spirals and can be a probe for the Stokes number in the disk.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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