Most stars form in a clustered environment. Both single and binary stars will sometimes encounter planetary systems in such crowded environments. Encounter rates for binaries may be larger than for single stars, even for binary fractions as low as 10-20 per cent. In this work, we investigate scatterings between a Sun-Jupiter pair and both binary and single stars as in young clusters. We first perform a set of simulations of encounters involving wide ranges of binaries and single stars, finding that wider binaries have larger cross sections for the planet's ejection. Secondly, we consider such scatterings in a realistic population, drawing parameters for the binaries and single stars from the observed population. The scattering outcomes are diverse, including ejection, capture/exchange and collision. The binaries are more effective than single stars by a factor of several or more in causing the planet's ejection and collision. Hence, in a cluster, as long as the binary fraction is larger than about 10 per cent, the binaries will dominate the scatterings in terms of these two outcomes. For an open cluster of a stellar density 50 pc$^{-3}$, a lifetime 100 Myr and a binary fraction 0.5, we estimate that of the order of 1 per cent of the Jupiters are ejected, 0.1 per cent collide with a star, 0.1 per cent change ownership and 10 per cent of the Sun-Jupiter pairs acquire a stellar companion during scatterings. These companions are typically 1000s of au distant and in half of the cases (so 5 per cent of all Sun-Jupiter pairs), they can excite the planet's orbit through Kozai--Lidov mechanism before stripped by later encounters. Our result suggests that the Solar System may have once had a companion in its birth cluster.

中文翻译：

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出生环境中涉及行星系统的遭遇：双星的重要作用

大多数恒星形成于星团环境中。在如此拥挤的环境中，单星和双星有时都会遇到行星系统。双星的遭遇率可能高于单星，即使双星的比例低至 10-20%。在这项工作中，我们研究了太阳-木星对与年轻星团中的双星和单星之间的散射。我们首先对涉及范围广泛的双星和单颗恒星的相遇进行了一组模拟，发现更宽的双星具有更大的用于行星喷射的横截面。其次，我们考虑现实群体中的这种散射，从观测群体中绘制双星和单星的参数。散射结果多种多样，包括喷射、捕获/交换和碰撞。双星在引起行星的抛射和碰撞方面比单颗恒星更有效。因此，在一个集群中，只要二元分数大于 10% 左右，就这两个结果而言，二元将主导散射。对于恒星密度为 50 pc$^{-3}$、寿命为 100 Myr 和二进制分数为 0.5 的疏散星团，我们估计大约 1% 的木星被喷出，0.1% 与一颗恒星，0.1% 的所有权变更，10% 的太阳-木星对在散射过程中获得了恒星伴星。这些伴星通常相距 1000 秒，在一半的情况下（因此占所有太阳-木星对的 5%），它们可以通过 Kozai--Lidov 机制激发行星的轨道，然后再被后来的遭遇剥离。