Core segregation during pebble accretion
Core segregation during pebble accretion
复制标题
卵石增生过程中的核心分离
DOI：
10.1016/j.epsl.2022.117537
复制
发表时间：
2022
影响因子：
5.3
通讯作者：
Garai, Susmita
中科院分区：
文献类型：
--
作者：
Olson, Peter;Sharp, Zachary;Garai, Susmita
我们提出了一个模型的类地行星形成的卵石吸积，专注于核心分离在早期地球。我们的研究结果表明，如果原地球和月球形成的撞击者忒伊亚是通过卵石吸积而生长的，那么在太阳系历史的最初几百万年内，每个天体中的核心形成金属都与地幔形成硅酸盐分离，而两者都被星云气体组成的大气所包围。吸收能量的大气层的热覆盖，铝-26的放射性衰变产生的热量，以及金属分离释放的引力能导致了非常高的内部温度，使得两个天体的地幔和核心在吸积过程中经历了部分或全部熔化。我们计算的压力-温度条件下的核心形成的金属被预测有分离下卵石增生岩浆海洋硅酸盐。这些条件的两体组合，代表合并的原地球和忒伊亚，产生平均分离压力和温度是类似的核心分离条件，以前推断的影响驱动的地球吸积限制金属硅酸盐分区的亲铁元素。
We present a model for terrestrial planet formation by pebble accretion, focusing on core segregation in the early Earth. Our results indicate that if the proto-Earth and the Moon-forming impactor Theia grew by pebble accretion, core-forming metals in each body segregated from mantle-forming silicates within the first few million years of solar system history, while both were enveloped in atmospheres composed of nebular gas. Thermal blanketing by their energy-absorbing atmospheres, heat produced by radioactive decay of aluminum-26, and gravitational energy released by metal segregation resulted in very high internal temperatures, such that the mantle and core of both bodies experienced partial or total melting during accretion. We calculate pressure-temperature conditions where the core-forming metals are predicted to have segregated from magma ocean silicates under pebble accretion. Two-body combinations of these conditions, representing the merger of proto-Earth and Theia, yield average segregation pressures and temperatures that are similar to core segregation conditions previously inferred for impact-driven Earth accretion constrained by metal-silicate partitioning of siderophile elements.