标题： 禁止线诊断光蒸发盘风 显示英文标题

标题： Forbidden line diagnostics of photoevaporative disc winds

摘要： 由中心恒星的高能辐射驱动的光致蒸发在原行星盘的演化中起着重要作用。 通过蓝移发射线已经明确检测到了光致蒸发风，但它们的详细特性仍不确定。 在这里，我们提出了一种新的经验方法，以对这些热风进行观测预测，旨在弥合理论与观测之间的差距。 我们使用了一个等温风的自相似模型来计算几种特征发射线（[Ne${\rm{\scriptsize II}}$]线在12.81 $\mu$m，以及光学禁戒线如[O${\rm{\scriptsize I}}$] 6300 $\mathring{A}$和 [S${\rm{\scriptsize II}}$] 4068/4076 $\mathring{A}$）的谱线轮廓，研究这些线如何受到气体温度、盘面倾角和密度分布等参数的影响。 我们的模型成功再现了具有$v_{\rm peak} \lesssim 10$ km/s的蓝移线，这些线随着盘面倾角的增加而减小。 线宽随着盘面倾角的增加而增大，范围从$\Delta v \sim 15-30$km/s。 预测的蓝移主要对气体声速敏感。 观测到的 [Ne${\rm{\scriptsize II}}$] 线轮廓与热风一致，并指向相对较高的声速，这符合极紫外光致蒸发的预期。 然而，观测到的 [O${\rm{\scriptsize I}}$] 线轮廓需要较低的温度，这符合 X 射线光致蒸发的预期，并显示出更宽的散布，这很难与单一风模型相协调；这些线条很可能追踪多相风的不同组分。 我们还注意到，当前观测的光谱分辨率仍然是这些研究中的一个重要限制因素，如果要通过发射线进一步理解原行星盘风，就需要更高分辨率的光谱。 显示英文摘要

摘要： Photoevaporation driven by high energy radiation from the central star plays an important role in the evolution of protoplanetary discs. Photoevaporative winds have been unambiguously detected through blue-shifted emission lines, but their detailed properties remain uncertain. Here we present a new empirical approach to make observational predictions of these thermal winds, seeking to fill the gap between theory and observations. We use a self-similar model of an isothermal wind to compute line profiles of several characteristic emission lines (the [Ne${\rm{\scriptsize II}}$] line at 12.81 $\mu$m, and optical forbidden lines such as [O${\rm{\scriptsize I}}$] 6300 $\mathring{A}$ and [S${\rm{\scriptsize II}}$] 4068/4076 $\mathring{A}$), studying how the lines are affected by parameters such as the gas temperature, disc inclinations, and density profile. Our model successfully reproduces blue-shifted lines with $v_{\rm peak} \lesssim 10$ km/s, which decrease with increasing disc inclination. The line widths increase with increasing disc inclinations and range from $\Delta v \sim 15-30$ km/s. The predicted blue-shifts are mostly sensitive to the gas sound speed. The observed [Ne${\rm{\scriptsize II}}$] line profiles are consistent with a thermal wind and point towards a relatively high sound speed, as expected for EUV photoevaporation. However, the observed [O${\rm{\scriptsize I}}$] line profiles require lower temperatures, as expected in X-ray photoevaporation, and show a wider scatter that is difficult to reconcile with a single wind model; it seems likely that these lines trace different components of a multi-phase wind. We also note that the spectral resolution of current observations remains an important limiting factor in these studies, and that higher resolution spectra are required if emission lines are to further our understanding of protoplanetary disc winds.