标题： 三维辐射流体动力学模拟过渡盘上的阴影 显示英文标题

标题： 3D Radiation-Hydrodynamical Simulations of Shadows on Transition Disks

摘要： 阴影经常出现在过渡盘中，这可能是由于靠近恒星的物质遮挡造成的，例如一个不对齐的内盘。 虽然阴影会留下明显的暗化辐射作为观测特征，但它们对盘有显著的动力学影响。 我们进行三维辐射流体动力学模拟来研究过渡盘中的阴影，并发现由于阴影导致的温度下降起到了不对称驱动力的作用，从而在空腔中形成螺旋结构。 这些螺旋结构具有零模式速度，跟随固定的阴影。 螺旋角由 tan$^{-1}$($c_s$/$v_\phi$) 给出（如果$h/r$=0.1，则为 6$^{\circ}$）。 这些螺旋结构能有效地通过空腔运输质量，在我们的模拟中为$\alpha \sim 10^{-2}$。 除了螺旋结构，空腔边缘还可以形成涡旋和絮状丝状结构。 当这些特征存在时，可能会干扰由阴影引起的螺旋结构。 通过进行蒙特卡洛辐射转移模拟，我们表明这些特征与近红外散射光图像中观察到的特征相似。 在垂直方向上，垂直重力不再仅由压力梯度平衡。 相反，方位向对流加速度项平衡了重力和压力的差异，导致方位向周期性的向上和向下气体运动，达到声速的10%，这可以通过ALMA线观测进行探测。 显示英文摘要

摘要： Shadows are often observed in transition disks, which can result from obscuring by materials closer to the star, such as a misaligned inner disk. While shadows leave apparent darkened emission as observational signatures, they have significant dynamical impact on the disk. We carry out 3D radiation hydrodynamical simulations to study shadows in transition disks and find that the temperature drop due to the shadow acts as an asymmetric driving force, leading to spirals in the cavity. These spirals have zero pattern speed following the fixed shadow. The pitch angle is given by tan$^{-1}$($c_s$/$v_\phi$) (6$^{\circ}$ if $h/r$=0.1). These spirals transport mass through the cavity efficiently, with $\alpha \sim 10^{-2}$ in our simulation. Besides spirals, the cavity edge can also form vortices and flocculent streamers. When present, these features could disturb the shadow-induced spirals. By carrying out Monte Carlo Radiative Transfer simulations, we show that these features resemble those observed in near-infrared scattered light images. In the vertical direction, the vertical gravity is no longer balanced by the pressure gradient alone. Instead, an azimuthal convective acceleration term balances the gravity-pressure difference, leading to azimuthally periodic upward and downward gas motion reaching 10% of the sound speed, which can be probed by ALMA line observations.