论文标题
过渡光盘I：2.5D全局模拟中的磁性风
Magnetised Winds in Transition Discs I: 2.5D Global Simulations
论文作者
论文摘要
原球盘（PPD）是见证行星形成的冷，密集和弱离子化的环境。在这些椎间盘中，过渡盘（TD）的特征是灰尘和气体分布的腔体广泛。尽管缺乏材料，但许多TD会强烈积聚其中心恒星，这可能表明机制正在驱动TDS腔中的快速积聚。 PPD中径向扩展的“死区”的存在最近恢复了对磁性碟中风（MDW）的兴趣，在该磁盘风（MDWS）中，积聚是由大磁场驱动的。我们建议TD可能会受到类似的风，从而解释了它们的快进和寿命长的腔。我们介绍了使用冥王星代码携带MDW的第一个2.5D全局数值模拟的结果。我们在气体分布中施加了一个空腔，并考虑了大规模磁场强度的功率定律分布。我们假设弱离子盘会受到双极扩散的影响，如在这一密度和温度范围内所预期的。我们的模拟TD具有内部空腔和外部“标准”圆盘的稳定状态。在整个光盘中，积聚速率保持大致恒定，达到典型的表面密度值的$ 10^{ - 7} 〜m_ \ odot/\ odot/\ text {yrs}^{ - 1} $。从腔体发射的MDW用比外盘发射的MDW大得多的杠杆臂更具磁化性。由于MDW施加的有效的磁制动，由于腔速度以声速增强腔体的材料，腔本身在开普勒速度的70％处旋转。总体而言，我们的腔体与黑洞物理学中内部喷射光盘（JED）和磁性逮捕的圆盘（MAD）的动力学特性相匹配。最后，运动学诊断（风速，轨道和积聚速度）可能会从MDW模型中解散经典的光蒸发。
Protoplanetary discs (PPDs) are cold, dense and weakly ionised environments that witness the planetary formation. Among these discs, transition discs (TDs) are characterised by a wide cavity in the dust and gas distribution. Despite this lack of material, many TDs strongly accrete onto their central star, possibly indicating that a mechanism is driving fast accretion in TDs cavities. The presence of radially extended 'dead zones' in PPDs recently revived the interest in magnetised disc winds (MDWs), where accretion is driven by a large magnetic field. We propose that TDs could be subject to similar winds, explaining their fast-accreting and long-lived cavities. We present the results of the first 2.5D global numerical simulations of TDs harbouring MDWs using the PLUTO code. We impose a cavity in the gas distribution and consider a power law distribution for the large-scale magnetic field strength. We assume weakly ionised discs subject to ambipolar diffusion, as expected in this range of densities and temperatures. Our simulated TDs reach a steady state with an inner cavity and an outer 'standard' disc. The accretion rates remain approximately constant through the entire discs, reaching $10^{-7}~M_\odot/\text{yrs}^{-1}$ for typical surface density values. The MDW launched from the cavity is more magnetised with a much larger lever arm than the MDW launched from the outer disc. The material in the cavity is accreted at sonic velocities, and the cavity itself is rotating at 70% of the Keplerian velocity due to the efficient magnetic braking imposed by the MDW. Overall, our cavity matches the dynamical properties of an inner jet emitting disc (JED) and of magnetically arrested discs (MADs) in black hole physics. Finally, kinematic diagnostics (wind speeds, orbital and accretion velocities) could disentangle classical photo-evaporation from MDW models.
