Fallback in core-collapse supernovae plays a crucial role in determining the properties of the compact remnants and of the ejecta composition. We perform three-dimensional simulations of mixing and fallback for selected non-rotating supernova models to study how explosion energy and asymmetries correlate with the remnant mass, remnant kick, and remnant spin. We find that the strongest kick and spin is imparted by partial fallback in an asymmetric explosion. Black hole (BH) kicks of several hundred $\mathrm{km}\,\mathrm{s}^{-1}$ and spin parameters of $\mathord{\sim}0.25$ can be obtained in this scenario. If the initial explosion energy barely exceeds the envelope binding energy, stronger fallback results, and the remnant kick and spin remain small. If the explosion energy is high with respect to the envelope binding energy, there is little fallback with a small effect on the remnant kick, but the spin-up by fallback can be substantial. For a non-rotating $12\,\mathrm{M}_\odot$ progenitor, we find that the neutron star (NS) is spun up to millisecond periods. The high specific angular momentum of the fallback material can also lead to disk formation around black holes. Fallback may thus be a pathway towards millisecond-magnetar or collapsar-type engines for hypernovae and gamma-ray bursts that does not require rapid progenitor rotation. Within our small set of simulations, none reproduced the peculiar layered fallback necessary to explain the metal-rich iron-poor composition of many carbon-enhanced metal-poor (CEMP) stars. Models with different explosion energy and different realisations of asymmetries may, however, be compatible with CEMP abundance patterns.

中文翻译：

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回落对核心坍缩超新星致密残骸和化学产率的影响

核心坍缩超新星的后退在确定致密残骸和喷射物成分的性质方面起着至关重要的作用。我们对选定的非旋转超新星模型进行混合和回退的三维模拟，以研究爆炸能量和不对称性如何与残余质量、残余冲击和残余自旋相关。我们发现最强的踢球和旋转是由不对称爆炸中的部分回落赋予的。在这种情况下可以获得数百 $\mathrm{km}\,\mathrm{s}^{-1}$ 的黑洞（BH）踢和 $\mathrd{\sim}0.25$ 的自旋参数。如果初始爆炸能量仅超过包络结合能，则会产生更强的回落，并且剩余的踢球和旋转保持很小。如果爆炸能相对于包膜结合能高，对剩余踢球的影响很小的后备很少，但后备的旋转可能很大。对于非旋转的 $12\,\mathrm{M}_\odot$ 前体，我们发现中子星 (NS) 旋转到毫秒级。后备物质的高比角动量也会导致黑洞周围的圆盘形成。因此，回退可能是通往不需要快速前身旋转的超新星和伽马射线爆发的毫秒磁星或塌陷型引擎的途径。在我们的一小组模拟中，没有人重现解释许多碳增强贫金属 (CEMP) 恒星的富金属贫铁组成所必需的特殊分层回退。然而，具有不同爆炸能量和不同不对称实现的模型可能与 CEMP 丰度模式兼容。