New long Chandra grating observations of the O supergiant $\zeta$ Pup show not only a brightening of the x-ray emission line flux of 13 per cent in the 18 years since Chandra's first observing cycle, but also clear evidence - at more than four sigma significance - of increased wind absorption signatures in its Doppler-broadened x-ray emission line profiles. We demonstrate this with non-parametric analysis of the profiles as well as Gaussian fitting and then use the line-profile model fitting to derive a mass-loss rate of $2.47 \pm 0.09 \times 10^{-6}$ Msun/yr, which is a 40 per cent increase over the value obtained from the cycle 1 data. The increase in the individual emission line fluxes is greater for short-wavelength lines than long-wavelength lines, as would be expected if a uniform increase in line emission is accompanied by an increase in the wavelength-dependent absorption by the cold wind in which the shock-heated plasma is embedded.

中文翻译：

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O 超巨星 ζ Puppis 的钱德拉光谱测量表明，18 年来风质量损失率惊人地增加

对 O 超巨星 $\zeta$ Pup 的新长钱德拉光栅观测显示，自钱德拉第一个观测周期以来的 18 年中，X 射线发射线通量不仅增亮了 13%，而且还有明确的证据——超过四个sigma 意义 - 在其多普勒展宽的 X 射线发射线剖面中增加的风吸收特征。我们通过剖面的非参数分析以及高斯拟合来证明这一点，然后使用线剖面模型拟合得出质量损失率为 $2.47 \pm 0.09 \times 10^{-6}$ Msun/yr，这比从周期 1 数据获得的值增加了 40%。短波长线的单个发射线通量的增加大于长波长线，