Kuiper Belt objects are thought to be formed at least a few million years after the formation of calcium–aluminum-rich inclusions (CAIs), at a time when the ²⁶Al isotope—the major source of radiogenic heat in the early solar system—had significantly depleted. The internal structure of these objects is highly dependent on any additional source that can produce extra heat in addition to that produced by the remaining, long-lasting radioactive isotopes. In this paper, we explore how serpentinization, the hydration of silicate minerals, can contribute to the heat budget and to what extent it can modify the internal structure of large Kuiper Belt objects. We find that the extent of restructuring depends very strongly on the start time of the formation process, the size of the object, and the starting ice-to-rock ratio. Serpentinization is able to restructure most of the interior of all objects in the whole size range (400–1200 km) and ice-to-rock ratio range investigated if the process starts early, ∼3 Myr after CAI formation, potentially leading to a predominantly serpentine core much earlier than previously thought (≤5 Myr versus several tens of million years). While the ratio of serpentinized material gradually decreases with the increasing formation time, the increasing ice-to-rock ratio, and the increasing start time of planetesimal formation in the outer solar system, in the case of the largest objects a significant part of the interior will be serpentinized even if the formation starts relatively late, ∼5 Myr after CAI formation. Therefore it is feasible that the interior of planetesimals may have contained a significant amount of serpentine, and in some cases, it could have been a dominant constituent, at the time of satellite-forming impacts.

中文翻译：

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蛇纹石化对大型柯伊伯带天体卫星形成碰撞初始条件的影响


柯伊伯带天体被认为是在富钙铝包裹体 (CAI) 形成后至少几百万年形成的，当时 ²⁶ Al 同位素（辐射热的主要来源）早期的太阳系——已经严重耗尽。这些物体的内部结构高度依赖于除了剩余的持久放射性同位素产生的热量之外，任何可以产生额外热量的额外来源。在本文中，我们探讨了蛇纹石化作用（硅酸盐矿物的水合作用）如何影响热量收支，以及它在多大程度上可以改变大型柯伊伯带天体的内部结构。我们发现重组的程度很大程度上取决于形成过程的开始时间、物体的大小以及起始的冰与岩石的比率。蛇纹石化作用能够在整个尺寸范围（400-1200公里）和冰石比范围内重组所有物体的大部分内部，如果这个过程开始得早，CAI形成后〜3 Myr，可能会导致主要蛇纹石核比之前认为的要早得多（≤5 Myr vs 几千万年）。虽然蛇纹石化物质的比例随着形成时间的增加、冰与岩石的比例的增加以及太阳系外行星形成的开始时间的增加而逐渐减少，但对于最大的天体来说，内部的重要部分即使形成开始相对较晚（CAI 形成后约 5 Myr），也会被蛇纹石化。因此，星子的内部可能含有大量的蛇纹石，并且在某些情况下，在卫星形成撞击时，它可能是主要成分。