KINEMATICS OF THE CO GAS IN THE INNER REGIONS OF THE TW Hya DISK
KINEMATICS OF THE CO GAS IN THE INNER REGIONS OF THE TW Hya DISK
复制标题
TW Hya DISK 内部区域 CO 气体的运动学
DOI：
10.1088/0004-637x/757/2/129
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
P. Ho
中科院分区：
文献类型：
--
作者：
K. Rosenfeld;C. Qi;S. Andrews;D. Wilner;S. Corder;C. Dullemond;Shin;A. Hughes;P. D’Alessio;P. Ho
基于阿塔卡马大型毫米/亚毫米阵列（阿尔马）的科学验证数据，对TW Hya拱星盘的12 CO J = 2-1和J = 3-2发射谱线进行了详细分析。这些谱线在其高速翼中显示出大量的辐射（投影速度高达2.1 km s−1，对应于大于20 km s−1的内禀轨道速度），这些辐射可以追踪到距离中心星星2 Au的分子气体。然而，我们无法重现这些翅膀的强度和一般的空间运动模式的线与简单的模型的磁盘结构和运动学。利用三维非局域热力学平衡分子激发和辐射传递计算，我们构建了一些替代模型，通过修改（1）内部盘的温度结构，（在灰尘耗尽的盘腔内; r < 4 Au），（2）内禀（开普勒）盘速度场，或（3）盘倾角分布（a翘曲）。后一种方法是特别引人注目的，因为一个有代表性的翘曲盘模型定性地再现了所观察到的散射光的盘表面的方位角调制。在任何模式的情况下，阿尔马数据显然需要一个实质性的分子气体水库位于该地区内的尘埃光学深度被称为大大减少TW Hya磁盘，在协议与以前的研究的基础上红外光谱。从这些更新的模型处方的结果进行了讨论，在其潜在的物理起源，其中可能包括动力学扰动，从一个低质量的同伴与几个Au的轨道分离。
We present a detailed analysis of the spatially and spectrally resolved 12CO J = 2–1 and J = 3–2 emission lines from the TW Hya circumstellar disk, based on science verification data from the Atacama Large Millimeter/submillimeter Array (ALMA). These lines exhibit substantial emission in their high-velocity wings (with projected velocities out to 2.1 km s−1, corresponding to intrinsic orbital velocities >20 km s−1) that trace molecular gas as close as 2 AU from the central star. However, we are not able to reproduce the intensity of these wings and the general spatio-kinematic pattern of the lines with simple models for the disk structure and kinematics. Using three-dimensional non-local thermodynamic equilibrium molecular excitation and radiative transfer calculations, we construct some alternative models that successfully account for these features by modifying either (1) the temperature structure of the inner disk (inside the dust-depleted disk cavity; r < 4 AU), (2) the intrinsic (Keplerian) disk velocity field, or (3) the distribution of disk inclination angles (a warp). The latter approach is particularly compelling because a representative warped disk model qualitatively reproduces the observed azimuthal modulation of optical light scattered off the disk surface. In any model scenario, the ALMA data clearly require a substantial molecular gas reservoir located inside the region where dust optical depths are known to be substantially diminished in the TW Hya disk, in agreement with previous studies based on infrared spectroscopy. The results from these updated model prescriptions are discussed in terms of their potential physical origins, which might include dynamical perturbations from a low-mass companion with an orbital separation of a few AU.