Modern studies of the early solar system routinely invoke the possibility of an orbital instability among the giant planets triggered by gravitational interactions between the planets and a massive exterior disk of planetesimals. Previous works have suggested that this instability can be substantially delayed (~100s Myr) after the formation of the giant planets. Bodies in the disk are typically treated in a semi-active manner, wherein their gravitational force on the planets is included, but interactions between the planetesimals are ignored. We perform N-body numerical simulations using GENGA, which makes use of GPUs to allow for the inclusion of all gravitational interactions between bodies. Although our simulated Kuiper belt particles are more massive than the probable masses of real primordial Kuiper belt objects, our simulations indicate that the self-stirring of the primordial Kuiper belt is very important to the dynamics of the giant planet instability. We find that interactions between planetesimals dynamically heat the disk and typically prevent the outer solar system instability from being delayed by more than a few tens of million years after giant planet formation. Longer delays occur in a small fraction of systems that have at least 3.5 AU gaps between the planets and planetesimal disk. Our final planetary configurations match the solar system at a rate consistent with other previous works in most regards. Pre-instability heating of the disk typically yields final Jovian eccentricities comparable to the modern solar system value, which has been a difficult constraint to match in past works.

中文翻译：

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自引力盘导致早期太阳系的不稳定性

对早期太阳系的现代研究通常会提出巨行星之间轨道不稳定的可能性，这种不稳定是由行星与巨大的小行星盘之间的引力相互作用引发的。之前的研究表明，这种不稳定性可以在巨行星形成后大大延迟（约 100 秒 Myr）。盘中的物体通常以半主动方式处理，其中包括它们对行星的引力，但忽略星子之间的相互作用。我们使用 GENGA 执行 N 体数值模拟，它利用 GPU 来包含物体之间的所有重力相互作用。尽管我们模拟的柯伊伯带粒子比真实的原始柯伊伯带天体的可能质量更大，但我们的模拟表明，原始柯伊伯带的自搅动对于巨行星不稳定性的动力学非常重要。我们发现，星子之间的相互作用动态地加热了圆盘，并且通常可以防止外太阳系的不稳定在巨行星形成后延迟数千万年以上。较长的延迟发生在一小部分系统中，这些系统的行星和星子盘之间至少有 3.5 个天文单位的间隙。我们最终的行星配置与太阳系的匹配速度在大多数方面与之前的其他工作一致。盘的不稳定前加热通常会产生与现代太阳系值相当的最终木星偏心率，这在过去的工作中是一个难以匹配的限制。