Correlated X-ray and optical variability in the O-type supergiant zeta Puppis

船尾座ζ I的详细X射线研究。数据集和一些初步结果

A detailed X-ray investigation of zeta Puppis I. The dataset and some preliminary results

目的：船尾座ζ是距离地球最近、最明亮的大质量恒星之一，是当代X射线观测站观测到的第一个早期类型的天体。这些数据提供了一些令人惊讶的结果，部分证实了理论预测，同时揭示了一些与预期不匹配的问题。在这一系列论文中，我们使用十年的XMM观测，对船尾座ζ在X射线中进行了彻底的研究。方法：用XMM观察船尾ζ 18次，共1Ms。这提供了迄今为止大质量恒星的最高质量高分辨率X射线光谱，以及研究“原型”物体中X射线变化的完美数据集。结果：这第一篇论文报告了这个独特的数据集的数据减少，并提供了一些初步的结果。一方面，EPIC低分辨率光谱的分析表明，从一次观测到下一次观测，该恒星具有非常稳定的X射线发射。另一方面，拟合风模型的个人线轮廓记录RGS确认的线形态的波长依赖性。

O型超巨星船尾座ζ的X射线谱线观测到的时代性变化并不要求星风质量通量发生实质性改变

Observed epochal variations in X-ray lines from the O Supergiant $ζ$ Puppis do not require substantial changes in the wind mass flux

通过变边界条件谱线模型拟合船尾座ζ的钱德拉X射线光谱，发现两个观测时期之间星风质量通量保持恒定，观测到的谱线变化源于激波形成位置向较大半径移动，而非整体星风增强。

Helium-like X-ray line complexes show that the hottest plasma on the O supergiant zeta Puppis is in its wind

We present an analysis of Chandra grating spectra of key helium-like line complexes to put constraints on the location with respect to the photosphere of the hottest ($T \gtrsim{6 \times 10^6}$ K) plasma in the wind of the O supergiant zeta Pup and to explore changes in the 18 years between two sets of observations of this star. We fit two models -- one empirical and one wind-shock-based -- to the S XV, Si XIII, and Mg XI line complexes and show that an origin in the wind flow, above $r \approx 1.5$ R$_{\ast}$, is strongly favored over an origin less than 0.3 R$_{\ast}$ above the photosphere (…

Chandra spectral measurements of the O supergiant $ζ$ Puppis indicate a surprising increase in the wind mass-loss rate over 18 years

New long Chandra grating observations of the O supergiant $ζ$ 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 …

A detailed X-ray investigation of zeta Puppis IV. Further characterization of the variability

Previously, the X-ray emission of zeta Puppis was found to be variable with light curves harbouring "trends" with a typical timescale longer than the exposure length. The origin of these changes was proposed to be linked to large-scale structures in the wind, but further characterization of the variability at high energies was needed. Since then, a number of new X-ray observations have become available. Furthermore, a cyclic behaviour with a 1.78d period was identified in long optical photometric runs, which is thought to be associated with the launching mechanism of large-scale wind structure…

船尾座ζ的详细X射线研究--短时间尺度和长时间尺度上的变化

A detailed X-ray investigation of zeta Puppis - The variability on short and long timescales

恒星风是大质量恒星的重要组成部分，但它们的确切性质仍然不确定。为了阐明这个问题，我们分析了一组特殊的X射线观测zeya Pup，这是最近和最明亮的大质量恒星之一。得出的灵敏度光变曲线揭示了两个主要结果。一方面，探测到X射线通量的缓慢调制（在0.3- 4.0keV波段，16小时内相对幅度高达15%）。其特征时间尺度无法精确确定，但从一天到几天不等。它可能与共转相互作用区域有关，已知存在于zeta Pup中的紫外线观测。在XMM观测所涵盖的过去十年中，没有观测到与耀斑或脉动活动有关的长达一小时的变化;先前在ROSAT分析中报告的17小时暂定周期也没有得到证实，因此充其量是短暂的。另一方面，短期的变化是令人惊讶的小（<1%的总能带的相对振幅）。事实上，它们只与数据中存在的泊松噪声兼容。考虑到嵌入的风激波起源，这种令人惊讶的低水平的短期变化需要非常高的恒星风碎片，无论是吸收还是发射特征（与二维风模型相比，>10^5个包裹）。这是第一次对O型星风和X射线观测中的团块数量进行限制。