标题： T Tauri星吸积和外流的氢发射 显示英文标题

标题： Hydrogen Emission from Accretion and Outflow in T Tauri Stars

摘要： 辐射传输建模为理解来自金牛T型星的神秘氢发射线提供了一种强大的工具。 这项工作将29颗金牛T型星的光学和近红外光谱与我们的合成线轮廓网格进行了比较。 存档的光谱是通过智利甚大望远镜（VLT）上的X-Shooter获得的，提供了许多光学和红外氢线的同时覆盖。 观测结果显示了与其他研究中看到的相似的线轮廓形态。 我们使用辐射传输代码TORUS为一个标准的金牛T型星模型创建了合成的H$\alpha$、Pa$\beta$、Pa$\gamma$和Br$\gamma$发射线，该模型包括轴对称磁层吸积和极区恒星风。 合成H$\alpha$线的Reipurth类型和线宽分布与观测结果相似。 然而，模型预测的红外线比观测值窄了$\approx 80{~\rm kms}^{-1}$倍，并且我们的模型预测了显著更高的反向P-Cygni谱线比例（$\approx 90$%）。 此外，我们的辐射转移模型表明，P-Cygni谱线的频率取决于质量损失率与吸积率的比值，并且预测出当质量损失率低至$10^{-12}~M_{\odot}{\rm~ yr}^{-1}$时会出现蓝移的次连续吸收。 我们探讨了旋转、湍流以及红移吸收贡献的影响，试图解释宽度之间的差异。 我们的研究结果显示，单独来看，这些效应中的任何一个都不足以解释观测到的差异。 然而，旋转、湍流和非轴对称吸积的结合可能会改善模型与观测数据之间的拟合度。 显示英文摘要

摘要： Radiative transfer modelling offers a powerful tool for understanding the enigmatic hydrogen emission lines from T Tauri stars. This work compares optical and near-IR spectroscopy of 29 T Tauri stars with our grid of synthetic line profiles. The archival spectra, obtained with VLT's X-Shooter, provide simultaneous coverage of many optical and infrared hydrogen lines. The observations exhibit similar morphologies of line profiles seen in other studies. We used the radiative transfer code TORUS to create synthetic H$\alpha$, Pa$\beta$, Pa$\gamma$, and Br$\gamma$ emission lines for a fiducial T Tauri model that included axisymmetric magnetospheric accretion and a polar stellar wind. The distribution of Reipurth types and line widths for the synthetic H$\alpha$ lines is similar to the observed results. However, the modelled infrared lines are narrower than the observations by $\approx 80{~\rm kms}^{-1}$, and our models predict a significantly higher proportion ($\approx 90$ per cent) of inverse P-Cygni profiles. Furthermore, our radiative transfer models suggest that the frequency of P-Cygni profiles depends on the ratio of the mass loss to mass accretion rates and blue-shifted sub-continuum absorption was predicted for mass loss rates as low as $10^{-12}~M_{\odot}{\rm~ yr}^{-1}$. We explore the effect of rotation, turbulence, and the contributions from red-shifted absorption in an attempt to explain the discrepancy in widths. Our findings show that, singularly, none of these effects is sufficient to explain the observed disparity. However, a combination of rotation, turbulence, and non-axisymmetric accretion may improve the fit of the models to the observed data.