We have studied the long-term (1971-2005) behaviour of the 1.24 sec pulse period and the 35 day precession period of Her X-1 and show that both periods vary in a highly correlated way (see also Staubert et al. 1997 and 2000). When the spin-up rate decreases, the 35 day turn-on period shortens.This correlation is most evident on long time scales (~2000 days),e.g.around four extended spin-down episodes, but also on shorter time scales (a few 100 days) on which quasi-periodic variations are apparent. We argue that the likely common cause is variations of the mass accretion rate onto the neutron star.The data since 1991 allow a continuous sampling and indicate a lag between the turn-on behaviour and the spin behaviour, in the sense that changes are first seen in the spin, about one cycle later in the turn-on. Both the coronal wind model (Schandl & Meyer 1994) as well as the stream-disk model (Shakura et al.999) predict this kind of behaviour.
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机译：我们研究了1.24秒脉冲周期和Her X-1的35天进动周期的长期（1971-2005年）行为，并表明这两个周期之间存在高度相关的变化（另请参见Staubert等，1997和2000）。当旋转速度降低时，35天的开启时间会缩短。这种相关性在较长的时间尺度（约2000天）中最为明显，例如大约四个扩展的旋转事件，但在较短的时间尺度中（几个100天），在此期间会出现明显的准周期变化。我们认为，可能的共同原因是中子星上质量吸积率的变化.1991年以来的数据允许进行连续采样，并表明在首次观察到变化的意义上开启行为和自旋行为之间存在滞后在旋转中，大约在开启后一个周期。日冕风模型（Schandl＆Meyer 1994）和流盘模型（Shakura et al.999）都预测了这种行为。
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