论文标题
环形积聚的流体动力学模拟：加热与冷却之间的平衡
Hydrodynamical Simulations of Circumbinary Accretion: Balance between Heating and Cooling
论文作者
论文摘要
环形圆盘（CBD）中的流体动力相互作用在各种天体物理系统中起着至关重要的作用，从年轻的恒星二进制组到银河系中心的超质量黑洞二进制。以前的大多数二进制式系统模拟都采用了当地等温州方程。在这项研究中，我们使用基于网格的代码$ \ texttt {achena ++} $来进行一套在笛卡尔网格上的循环积聚的二维粘性水动力学模拟，从而解决了二元的中心空腔。气体热力学通过热放松对平衡温度进行处理（基于常数$-β$冷却ansatz，其中$β$是本地开普勒时间单位的冷却时间）。侧重于相等的质量，具有（平衡）盘纵横比$ h/r = 0.1 $的CBD中的圆形二进制文件，我们发现盘式气体的冷却显着影响二进制轨道的演化，积聚性变异性和CBD形态，效果敏感地取决于盘式粘度的效果。在采用恒定运动粘度时，有限的冷却时间（$β\ gtrsim 0.1 $）会导致二进制灵感，而不是巨型精神，而CBD腔变得更加对称。当采用动态变化的$α-$粘度时，二进制灵感仅发生在狭窄的冷却时间范围内（对应于0.5左右的$β$）。
Hydrodynamical interaction in circumbinary discs (CBDs) plays a crucial role in various astrophysical systems, ranging from young stellar binaries to supermassive black hole binaries in galactic centers. Most previous simulations of binary-disc systems have adopted locally isothermal equation of state. In this study, we use the grid-based code $\texttt{Athena++}$ to conduct a suite of two-dimensional viscous hydrodynamical simulations of circumbinary accretion on a cartesian grid, resolving the central cavity of the binary. The gas thermodynamics is treated by thermal relaxation towards an equilibrium temperature (based on the constant$-β$ cooling ansatz, where $β$ is the cooling time in units of the local Keplerian time). Focusing on equal mass, circular binaries in CBDs with (equilibrium) disc aspect ratio $H/R=0.1$, we find that the cooling of the disc gas significantly influences the binary orbital evolution, accretion variability, and CBD morphology, and the effect depends sensitively on the disc viscosity prescriptions. When adopting a constant kinematic viscosity, a finite cooling time ($β\gtrsim 0.1$) leads to binary inspiral as opposed to outspiral and the CBD cavity becomes more symmetric. When adopting a dynamically varying $α-$viscosity, binary inspiral only occurs within a narrow range of cooling time (corresponding to $β$ around 0.5).
