Thermal consequences of impacts in the early solar system
Thermal consequences of impacts in the early solar system
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DOI：
10.1111/maps.12236
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发表时间：
2013-12-01
影响因子：
2.2
通讯作者：
O'Brien, David P.
中科院分区：
文献类型：
--
作者：
Ciesla, Fred J.;Davison, Thomas M.;O'Brien, David P.
在太阳系形成的第一个大约1亿年期间，星子之间的碰撞是常见的。这种碰撞被认为是造成某些陨石中的热过程的原因，尽管以前的工作已经表明，这种事件不可能是造成陨石母体的全球热演化的原因。然而，在太阳系历史的早期，陨石母体可能已经被加热或保留了短寿命放射性核素衰变的热量，最明显的是Al-26。在这里示出的受冲击体的后冲击结构是目标体的内部温度结构的强函数。我们计算的所有质量在这些受影响的机构的温度-时间的历史，占他们的加热在洋葱壳结构的身体之前的碰撞事件，然后允许的postimpact热演化的热量从两个放射性和影响是通过产生的星子扩散和辐射到空间。这些机构中的材料的热历史进行比较，他们将在一个未受影响的，洋葱壳机构。我们发现，虽然早期太阳系中的碰撞导致了撞击点周围目标物体的加热，但由于在撞击坑事件期间加热的材料流向表面，更大量的质量加速了其冷却速率。
Collisions between planetesimals were common during the first approximately 100Myr of solar system formation. Such collisions have been suggested to be responsible for thermal processing seen in some meteorites, although previous work has demonstrated that such events could not be responsible for the global thermal evolution of a meteorite parent body. At this early epoch in solar system history, however, meteorite parent bodies would have been heated or retained heat from the decay of short-lived radionuclides, most notably Al-26. The postimpact structure of an impacted body is shown here to be a strong function of the internal temperature structure of the target body. We calculate the temperature-time history of all mass in these impacted bodies, accounting for their heating in an onion-shell-structured body prior to the collision event and then allowing for the postimpact thermal evolution as heat from both radioactivities and the impact is diffused through the resulting planetesimal and radiated to space. The thermal histories of materials in these bodies are compared with what they would be in an unimpacted, onion-shell body. We find that while collisions in the early solar system led to the heating of a target body around the point of impact, a greater amount of mass had its cooling rates accelerated as a result of the flow of heated materials to the surface during the cratering event.