AI 中文总结
本研究通过高分辨率全局MHD模拟，揭示嵌入磁化吸积盘的低质量扰动体可自然形成带大尺度磁场的微型吸积盘及双极磁外流，为相关天体物理模型奠定基础。
AI 中文摘要
我们展示了迄今为止关于嵌入大质量中心天体吸积盘中的低质量扰动体（质量比$q\in[10^{-4},10^{-3}]$）周围气体流动的最高分辨率全局MHD模拟。我们发现，流向次级天体的气体自洽地形成了一个湍流、磁化的微型吸积盘。该微型吸积盘维持着由MRI（磁旋转不稳定性）的发电机效应及流入扰动体的吸积流所产生的大尺度磁场。同时，还会发射出双极、准直、磁化的外流，其延伸范围超过扰动体的希尔球。双极外流由微型吸积盘最内侧区域的磁压，以及气体的磁离心加速共同驱动，气体速度可达到与大质量中心天体的逃逸速度相当的水平。我们的结果在吸积盘物理中建立了跨广泛天体物理系统的重要概念联系——从微型吸积盘到星周盘及黑洞吸积盘——证明小型盘无需精细调谐即可自然进入外流发射状态。除了确定驱动小型外流的物理机制外，我们的框架为开发嵌入低质量扰动体周围微型吸积盘的更复杂物理模型奠定了基础。
英文摘要
We present the highest resolution global MHD simulations to date of gas flow around a low mass a perturber with mass ratio $q\in[10^{-4},10^{-3}]$, embedded in an accretion disk around a massive central object. We find that gas flow onto the secondary self-consistently forms a turbulent, magnetized mini-accretion disk. The mini-accretion disk sustains a large-scale magnetic field generated by the dynamo effect of the MRI and the accretion flow into the perturber. Simultaneously, a bipolar, collimated, magnetized outflow is launched, extending beyond the perturber's Hill sphere. The bipolar outflows are driven by the combined action of magnetic pressure, in the innermost regions of the mini-accretion disk, and the magnetocentrifugal acceleration of gas, which may attain speeds comparable to the escape velocity from the massive central object. Our results establish an important conceptual connection in accretion disk physics across a wide range of astrophysical systems -from mini-accretion disks to circumstellar and black hole accretion disks-by demonstrating that no fine-tuning is required for small-scale disks to naturally enter an outflow-launching regime. Beyond identifying the physical mechanism responsible for launching small-scale outflows, our framework lays the groundwork for developing more sophisticated physical models of mini-accretion disks around embedded low-mass perturbers.
Comments9 pages, 10 figures, accepted for publication in A&A
