论文标题
高分辨率X射线的深入曝光揭示了$ζ\，$ puppis风中最热的等离子体
A Deep Exposure in High Resolution X-Rays Reveals the Hottest Plasma in the $ζ\,$Puppis Wind
论文作者
论文摘要
我们已经获得了带有Chandra/hetg光谱仪的$ζ\（O4 Supergiant）的非常深的曝光（813 KS）。在这里，我们报告了对1-9Å区域的分析，特别适合Chandra，该地区对来自高离子化物种的良好分离排放线之间的连续发射具有很大的贡献。这些数据使我们能够通过连续形状和发射线强度研究最热的血浆。假设具有高温截止的PowerLaw发射测量分布，我们发现该发射与具有12 mk最高温度的热光谱一致。这意味着有效的风力冲击速度为$ 900 \，\ mathrm {km \，s^{ - 1}} $，远低于$ 2250 \，\ mathrm {kmm \，s^{ - 1}}} $的风端端速度。对于X射线发射，与恒星接近的X射线发射相比，速度和X射线通量要比严格自我激发的线降低稳定模型轻松地对帐，这表明需要从基座上极快地加速风速。这不是动态不稳定性，而是对变化边界条件的非线性响应。
We have obtained a very deep exposure (813 ks) of $ζ\,$Puppis (O4 supergiant) with the Chandra/HETG Spectrometer. Here we report on analysis of the 1-9 Å region, especially well suited for Chandra, which has a significant contribution from continuum emission between well separated emission lines from high-ionization species. These data allow us to study the hottest plasma present through the continuum shape and emission line strengths. Assuming a powerlaw emission measure distribution which has a high-temperature cut-off, we find that the emission is consistent with a thermal spectrum having a maximum temperature of 12 MK. This implies an effective wind shock velocity of $900\,\mathrm{km\,s^{-1}}$, well below the wind terminal speed of $2250\,\mathrm{km\,s^{-1}}$. For X-ray emission which forms close to the star, the speed and X-ray flux are larger than can be easily reconciled with strictly self-excited line-deshadowing-instability models, suggesting a need for a fraction of the wind to be accelerated extremely rapidly right from the base. This is not so much a dynamical instability as a nonlinear response to changing boundary conditions.
