The end of runaway: how gap opening limits the final masses of gas giants
The end of runaway: how gap opening limits the final masses of gas giants
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失控的终结：间隙的打开如何限制气态巨行星的最终质量
DOI：
10.1093/mnras/stz1322
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发表时间：
2019
影响因子：
4.8
通讯作者：
E. Chiang
中科院分区：
文献类型：
--
作者：
S. Ginzburg;E. Chiang
气体巨星被认为是由失控的吸积形成的：一种由不断增长的大气层的自引力驱动的不稳定性，导致吸积率随行星质量超线性上升。为什么逃逸会在木星或任何其他质量时停止，这是未知的。我们考虑的建议，最终的质量是由行星引力矩打开的拱星盘间隙（腔）控制。我们开发了一个完全依赖于时间的间隙形成理论，并将其自洽地耦合到行星的增长率。当间隙第一次打开时，行星扭矩超过粘性扭矩，气体耗尽，就像它是无粘性的一样。在低粘度盘中，最近的观测和理论激发了这种类型，间隙主要停留在这个无粘阶段，行星质量最终在$M_{\rm final}/M_\星星\sim（\Omega t_{\rm disc}）^{0.07}（H/a）^{2.73}（G\rho_0/\Omega^2）^{1/3}$，其中$M_\星星$为宿主恒星质量，$\Omega $为行星轨道角速度，$t_{\rm disc}$为气盘寿命，$H/a $为长宽比，和它的未扰动密度。这个最终的质量与无量纲粘度$\alpha $无关，并且适用于大的轨道距离，通常超过$\sim$10 Au，在那里圆盘尺度高度超过行星半径。它的质量估计在10 - 100 Au之间，随着距离的增加而逐渐增加，因为间隙变得更难打开。
Gas giants are thought to form by runaway accretion: an instability driven by the self-gravity of growing atmospheres that causes accretion rates to rise super-linearly with planet mass. Why runaway should stop at a Jupiter or any other mass is unknown. We consider the proposal that final masses are controlled by circumstellar disc gaps (cavities) opened by planetary gravitational torques. We develop a fully time-dependent theory of gap formation and couple it self-consistently to planetary growth rates. When gaps first open, planetary torques overwhelm viscous torques, and gas depletes as if it were inviscid. In low-viscosity discs, of the kind motivated by recent observations and theory, gaps stay predominantly in this inviscid phase and planet masses finalize at $M_{\rm final}/M_\star\sim(\Omega t_{\rm disc})^{0.07}(H/a)^{2.73}(G\rho_0/\Omega^2)^{1/3}$, with $M_\star$ the host stellar mass, $\Omega$ the planet's orbital angular velocity, $t_{\rm disc}$ the gas disc's lifetime, $H/a$ its aspect ratio, and $\rho_0$ its unperturbed density. This final mass is independent of the dimensionless viscosity $\alpha$ and applies to large orbital distances, typically beyond $\sim$10 AU, where disc scale heights exceed planet radii. It evaluates to a few Jupiter masses at 10-100 AU, increasing gradually with distance as gaps become harder to open.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell