X-rays give direct evidence of instabilities, time-variable structure, and shock heating in the winds of O stars. The observed broad X-ray emission lines provide information about the kinematics of shock-heated wind plasma, enabling us to test wind-shock models. And their shapes provide information about wind absorption, and thus about the wind mass-loss rates. Mass-loss rates determined from X-ray line profiles are not sensitive to density-squared clumping effects, and indicate mass-loss rate reductions of factors of 3 to 6 over traditional diagnostics that suffer from density-squared effects. Broad-band X-ray spectral energy distributions also provide mass-loss rate information via soft X-ray absorption signatures. In some cases, the degree of wind absorption is so high, that the hardening of the X-ray SED can be quite significant. We discuss these results as applied to the early O stars zeta Pup (O4 If), 9 Sgr (O4 V((f))), and HD 93129A (O2 If*).
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机译：X射线可以直接证明O恒星的风中存在不稳定性，时变结构和激波加热。观察到的宽X射线发射线可提供有关激波加热的风等离子体运动学的信息，从而使我们能够测试风冲击模型。它们的形状提供了有关风吸收的信息，从而提供了风的质量损失率。由X射线线轮廓确定的质量损失率对密度平方的成簇效应不敏感，并且表明质量损失率与受密度平方效应影响的传统诊断方法相比降低了3到6倍。宽带X射线光谱能量分布还通过软X射线吸收特征提供质量损失率信息。在某些情况下，吸风程度很高，以至于X射线SED的硬化可能非常显着。我们讨论了应用于早期O型星zeta Pup（O4 If），9 Sgr（O4 V（（f）））和HD 93129A（O2 If *）的结果。
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