论文标题
加油在带有层流积聚的圆盘中的木星质量行星上
Gas accretion onto Jupiter mass planets in discs with laminar accretion flows
论文作者
论文摘要
（删节的）研究表明，嵌入粘性原球盘（PPD）中的Jovian质量行星可以通过间隙有效地积聚气体，并在$ \ sim 0.1 $ MYR中增加一倍的质量。该星球还以$ \ sim 0.1 $ MYR的时间尺度向内迁移。与PPD寿命相比，这些时间尺度很短，并提出了有关冷巨型系外行星的起源的问题。但是，PPD不太可能是全球动荡的，相反，它们可能会发出磁性的风，从而使恒星的积聚发生在椎间盘表面附近的狭窄层的层状积聚流中。这项研究的目的是检查嵌入在分层PPD中的Jovian质量行星上的气体增生的速率。我们使用嵌入PPD中的行星的3D流体动力模拟，其中持续的径向质量通量向$ {\ dot m} = 10^{ - 8} $ m $ _ {\ odot} $ yr $^{ - 1} $的恒星。我们考虑了经典的粘性α模型，还考虑了在狭窄的表面层中施加外部扭矩以模仿磁化风的效果。积分层由其列密度$σ_ {\ rm a} $进行参数化，我们考虑在0.1至10 g cm $^{ - 2} $的范围内的值。粘性模型与以前的研究一致。我们发现，在分层模型中的积聚率至关重要地取决于行星阻断风引起的质量流量的能力。对于$σ_ {\ rm a} = 10 $ g cm $^{ - 2} $，行星扭矩可以阻止质量流穿过光盘，积聚到行星上很慢，并且获得了10 Myr的质量加倍时间。对于$σ_ {\ rm a} = 0.1 $ g cm $^{ - 2} $，积聚很快，质量加倍时间为0.2 Myr。尽管穿过分层圆盘模型的径向质量流始终为$ 10^{ - 8} $ m $ _ {\ odot} $ yr $^{ - 1} $，但采用$σ_ {\ rm a} $的不同值导致对汽油巨型行星的质量非常不同的气体积聚率。
(Abridged) Studies have shown that a Jovian mass planet embedded in a viscous protoplanetary disc (PPD) can accrete gas efficiently through the gap and doubles its mass in $\sim 0.1$ Myr. The planet also migrates inwards on a timescale of $\sim 0.1$ Myr. These timescales are short compared to PPD lifetimes, and raise questions about the origins of cold giant exoplanets. However, PPDs are unlikely to be globally turbulent, and instead they may launch magnetised winds such that accretion towards the star occurs in laminar accretion flows located in narrow layers near the surfaces of the disc. The aim of this study is to examine the rate at which gas accretes onto Jovian mass planets that are embedded in layered PPDs. We use 3D hydrodynamical simulations of planets embedded in PPDs, in which a constant radial mass flux towards the star of ${\dot m} = 10^{-8}$ M$_{\odot}$ yr$^{-1}$ is sustained. We consider a classical viscous alpha model, and also models in which an external torque is applied in narrow surface layers to mimic the effects of a magnetised wind. The accreting layers are parameterised by their column densities $Σ_{\rm A}$, and we consider values in the range 0.1 to 10 g cm$^{-2}$. The viscous model gives results in agreement with previous studies. We find the accretion rate onto the planet in the layered models crucially depends on the planet's ability to block the wind-induced mass flow. For $Σ_{\rm A}=10$ g cm$^{-2}$, the planet torque can block the mass flow through the disc, accretion onto the planet is slow, and a mass doubling time of 10 Myr is obtained. For $Σ_{\rm A}=0.1$ g cm$^{-2}$, accretion is fast and the mass doubling time is 0.2 Myr. Although the radial mass flow through the layered disc models is always $10^{-8}$ M$_{\odot}$ yr$^{-1}$, adopting different values of $Σ_{\rm A}$ leads to very different gas accretion rates onto gas giant planets.
