We present spectroscopy of the P Cygni profile of the 1.083-$\mu$m He i line in the WC7+O5 colliding-wind binary (CWB) WR 140 (HD 193793), observed in 2008, before its periastron passage in 2009, and in 2016–2017, spanning the subsequent periastron passage. Both absorption and emission components showed strong variations. The variation of the absorption component as the O5 star was occulted by the wind-collision region (WCR) sets a tight constraint on its geometry. While the sightline to the O5 star traversed the WCR, the strength and breadth of the absorption component varied significantly on time-scales of days. An emission subpeak was observed on all our profiles. The variation of its radial velocity with orbital phase was shown to be consistent with formation in the WCR as it swung round the stars in their orbit. Modelling the profile gives a measure of the extent of the subpeak-forming region. In the phase range 0.93–0.99, the flux in the subpeak increased steadily, approximately inversely proportionally to the stellar separation, indicating that the shocked gas in the WCR where the line was formed was adiabatic. After periastron, the subpeak flux was anomalously strong and varied rapidly, suggesting formation in clumps downstream in the WCR. For most of the time, its flux exceeded the 2–10-keV X-ray emission, showing it to be a significant coolant of the shocked wind.

中文翻译：

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1.083-μ m He i 线剖面揭示的 WR 140 风碰撞区域的条件

我们展示了 WC7+O5 碰撞风双星 (CWB) WR 140 (HD 193793) 中 1.083-$\mu$m He i 线的天鹅座 P 剖面光谱，该光谱于 2008 年观测到，在 2009 年近星体通过之前，并在 2016-2017 年跨越随后的近星通道。吸收和发射成分都表现出强烈的变化。当 O5 星被风碰撞区域 (WCR) 掩蔽时，吸收分量的变化对其几何形状设置了严格的限制。当 O5 星的视线穿过 WCR 时，吸收成分的强度和广度在天的时间尺度上变化很大。在我们所有的配置文件中都观察到了发射亚峰。它的径向速度随轨道相位的变化被证明与 WCR 中的形成一致，因为它围绕轨道上的恒星旋转。对轮廓建模给出了亚峰形成区域范围的测量。在 0.93~0.99 相位范围内，子峰内的通量稳步增加，与星距大致成反比，说明形成谱线的 WCR 中的激波气体是绝热的。在近星体之后，次峰通量异常强且变化迅速，表明在西中央下游形成团块。在大多数情况下，它的通量超过了 2-10 keV X 射线发射，表明它是冲击风的重要冷却剂。在近星体之后，次峰通量异常强且变化迅速，表明在西中央下游形成团块。在大多数情况下，它的通量超过了 2-10 keV X 射线发射，表明它是冲击风的重要冷却剂。在近星体之后，次峰通量异常强且变化迅速，表明在西中央下游形成团块。在大多数情况下，它的通量超过了 2-10 keV X 射线发射，表明它是冲击风的重要冷却剂。