Chondritic meteorites are thought to be representative of the material that formed the Earth. However, the Earth is depleted in volatile elements in a manner unlike that observed in any chondrite, and yet these elements retain chondritic isotope ratios. Here we use N-body simulations to show that the Earth did not form only from chondrites, but by stochastic accretion of many precursor bodies whose variable compositions reflect the temperatures at which they formed. Earth’s composition is reproduced when the initial temperatures of planetesimal- to embryo-sized bodies are set by disk accretion rates of (1.08 ± 0.17) × 10⁻⁷ solar masses per year, although they may be perturbed by ²⁶Al heating on bodies formed at different times. Our model implies that a heliocentric gradient in composition was present in the protoplanetary disk and that planetesimals formed rapidly within ~1 Myr, consistent with radiometric volatile depletion ages of the Earth.

球粒陨石被认为是形成地球的物质的代表。然而，地球以不同于在任何球粒陨石中观察到的方式耗尽挥发性元素，但这些元素仍保留球粒陨石同位素比率。在这里，我们使用N体模拟来表明地球不仅是由球粒陨石形成的，而且是由许多前体的随机吸积形成的，这些前体的可变成分反映了它们形成时的温度。当小行星到胚胎大小的天体的初始温度由每年(1.08 ± 0.17) × 10 ^-7个太阳质量的圆盘吸积率设定时，地球的成分就会重现，尽管它们可能会受到^{26个太阳质量的扰动。}在不同时间形成的物体上的铝加热。我们的模型表明，原行星盘中存在日心成分梯度，并且小行星在约 1 Myr 内迅速形成，这与地球的辐射挥发耗竭年龄一致。