论文标题
在狼射线星的风中聚集
Clumping in the Winds of Wolf-Rayet Stars
论文作者
论文摘要
我们试图通过扩展银河狼射线星的光谱变异水平到迄今为止最热门的频谱变化水平，WN2 Star WR 2和WO2 Star Star wr 102和WR 142。 WR恒星的全温度范围比O-Star祖细胞（约30-50 KK）的温度宽得多，因此更适合查找风块的任何温度依赖性。我们已经获得了多个观测值，这些观察值是从这三个极端恒星的密集风中搜索强发射线中的小尺度变异性，并在这两个恒星中找到非常低的可变性。温度和终端速度相关，因此更快的风显示出较低的变异性，尽管这种趋势与任何涉及线取消不稳定性（LDI）的预测违背，这意味着LDI的不稳定性并不是风结块的主要来源。取而代之的是，它可以作为支持团块是由T〜170 KK处的地下对流区（SSCZ）引起的，因为这样的SSCZ几乎没有机会在这些最热的WR恒星的静水表面下进行操作。但是，与SSCZ相关的驱动器可能会与非线性线不稳定性效应相互作用，从而增强甚至可能产生团块。
We attempt to determine the driver for clumping in hot-star winds by extending the measure of the spectral variability level of Galactic Wolf-Rayet stars to by far the hottest known among them, the WN2 star WR 2 and the WO2 stars WR 102 and WR 142. These three stars have T* = 140 kK and 200 kK, the last two being well above the bulk of WR stars with T* ~ 40-120 kK. This full temperature range for WR stars is much broader than that of their O-star progenitors (~30-50 kK), so is better suited to look for any temperature dependence of wind clumping. We have obtained multiple observations with high signal-to-noise, moderate-resolution spectroscopy in search of smallscale variability in the strong emission lines from the dense winds of these three extreme stars, and find a very low-level of variability in both stars. Temperature and terminal velocity are correlated, so faster winds show a lower variability, though this trend goes against any predictions made involving Line Deshadowing Instability (LDI) only, implying that instabilities intrinsic to LDI are not the main source of wind clumping. Instead, it could be taken as support for the suggestion that clumps are caused by a sub-surface convection zone (SSCZ) at T ~ 170 kK, since such an SSCZ would have little opportunity to operate under the hydrostatic surface of these hottest WR stars. It is still possible, however, that an SSCZ-related driver could interact with nonlinear line instability effects to enhance or possibly even produce clumps.
