Recent high-precision meteoritic data infers that Mars finished its accretion rapidly within 10 Myr of the beginning of the Solar System and had an accretion zone that did not entirely overlap with the Earth’s. Here we present a detailed study of the accretion zone of planetary embryos from high-resolution simulations of planetesimals in a disk. We found that all simulations with Jupiter and Saturn on their current eccentric orbits (EJS) result in a similar accretion zone between fast-forming Mars and Earth-region embryos. Assuming more circular orbits for Jupiter and Saturn (CJS), on the other hand, has a significantly higher chance of forming Mars with an accretion zone not entirely dominated by Earth and Venus-region embryos; however, CJS in general forms Mars slower than in EJS. By further quantifying the degree of overlap between accretion zones of embryos in different regions with the average overlap coefficient (OVL), we found that the OVL of CJS shows a better match with the OVL from a chondritic isotopic mixing model of Earth and Mars, which indicates that the giant planets are likely to have resided on more circular orbits during gas disk dissipation than they do today, matching their suggested pre-instability orbits. More samples, including those from Mercury and Venus, could potentially confirm this hypothesis.

最近的高精度陨石数据推断，火星在太阳系开始的 10 Myr 内迅速完成了吸积，并且有一个与地球不完全重叠的吸积带。在这里，我们从圆盘中小行星的高分辨率模拟中详细研究了行星胚胎的吸积区。我们发现，木星和土星在其当前偏心轨道 (EJS) 上的所有模拟都会导致快速形成的火星和地球区域胚胎之间存在类似的吸积区。另一方面，假设木星和土星（CJS）有更多的圆形轨道，形成火星的可能性要高得多，其吸积带不完全由地球和金星区域的胚胎主导；然而，CJS 通常比 EJS 更慢地形成火星。通过用平均重叠系数（OVL）进一步量化不同区域胚胎吸积带之间的重叠程度，我们发现CJS的OVL与地球和火星球粒陨石同位素混合模型的OVL表现出更好的匹配性，即表明在气盘消散期间，巨行星可能驻留在比今天更多的圆形轨道上，与它们建议的不稳定前轨道相匹配。更多的样本，包括来自水星和金星的样本，可能会证实这一假设。这表明在气体盘耗散期间，巨行星可能驻留在比今天更多的圆形轨道上，与它们建议的不稳定前轨道相匹配。更多的样本，包括来自水星和金星的样本，可能会证实这一假设。这表明在气体盘耗散期间，巨行星可能驻留在比今天更多的圆形轨道上，与它们建议的不稳定前轨道相匹配。更多的样本，包括来自水星和金星的样本，可能会证实这一假设。