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arXiv 1406.3989astro-ph.SR
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AA Tau的谱线和连续辐射转移模拟

Line and continuum radiative transfer modelling of AA Tau

C. F. Esau, T. J. Harries, J. Bouvier

摘要:

我们提出的光度和光谱模型的经典金牛座T星AA头。光度和光谱的变化目前在AA头的观测是由于磁致翘曲的吸积盘,周期性地掩盖光球的8.2天的时间尺度。发射线轮廓显示的签名,这两个下降,归因于磁层吸积材料,和外流。使用辐射转移程序TORUS,我们研究了AA Tau的拱星盘和外流的几何和运动学,这里模拟为盘风。光度模型已被用来约束的磁盘的纵横比,磁层偶极子相对于恒星旋转轴的偏移角,和拱盘的内半径。光谱模型已被用来约束风和磁层温度,风加速度参数,和质量损失率。我们发现观测结果与质量吸积率为$5\times10^{-9}$ M $_\odot$ yr $^{-1}$的模型拟合得最好,偶极偏移在$10^\circ$和$20^\circ$之间,磁层将盘从5.2 R截断到8.8 R $_\star$,质量损失率与吸积率之比约为0.1,磁层温度为8500 - 9000 K,盘风温度为8000 K。

英文摘要:

We present photometric and spectroscopic models of the Classical T Tauri star AA Tau. Photometric and spectroscopic variability present in observations of AA Tau is attributed to a magnetically induced warp in the accretion disc, periodically occulting the photosphere on an 8.2--day timescale. Emission line profiles show signatures of both infall, attributed to magnetospherically accreting material, and outflow. Using the radiative transfer code TORUS, we have investigated the geometry and kinematics of AA Tau's circumstellar disc and outflow, which is modelled here as a disc wind. Photometric models have been used to constrain the aspect ratio of the disc, the offset angle of the magnetosphere dipole with respect to the stellar rotation axis, and the inner radius of the circumstellar disc. Spectroscopic models have been used to constrain the wind and magnetosphere temperatures, wind acceleration parameter, and mass loss rate. We find observations are best fitted by models with a mass accretion rate of $5\times10^{-9}$ M$_\odot$ yr$^{-1}$, a dipole offset of between $10^\circ$ and $20^\circ$, a magnetosphere that truncates the disc from 5.2 to 8.8 R$_\star$, a mass-loss-rate to accretion-rate ratio of ~ 0.1, a magnetosphere temperature of 8500 -- 9000 K, and a disc wind temperature of 8000 K.

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