Transfer, loss and physical processing of water in hit-and-run collisions of planetary embryos.
Transfer, loss and physical processing of water in hit-and-run collisions of planetary embryos.
复制标题
DOI：
10.1007/s10569-017-9795-3
复制
发表时间：
2018
影响因子：
1.6
通讯作者：
Schäfer CM
中科院分区：
文献类型：
--
作者：
Burger C;Maindl TI;Schäfer CM
类似大小的大型天体之间的碰撞被认为会塑造类地行星的最终特征和组成。它们的挥发物（如水）库存要么被这些事件传递，要么至少被这些事件显著改变。除了随着撞击速度的增加从吸积到侵蚀的转变之外，如果撞击角度足够倾斜，弹靶质量比足够大，类似规模的碰撞也可能导致打了就跑的结果。我们研究挥发物的转移和损失集中在打了就跑的遭遇通过光滑粒子流体动力学模拟，包括所有的主要参数：碰撞速度，碰撞角度，质量比，也总碰撞质量。我们发现了一个广泛的整体水的损失，高达75%，在最充满活力的打了就跑的事件，并确认更严重的后果，为较小的机构也为剥离的挥发层。水之间的传输被认为是大多数是相当低效的，和最终的水含量占主导地位的碰撞前库存减少的影响损失，类似的碰撞前水的质量分数。与我们的数值结果的比较表明，目前的碰撞结果模型是不够准确的，可靠地预测这些组成的变化打了就跑事件。为了解释非机械损失，我们估计了在广泛的质量范围内碰撞蒸发的水的量，并发现这些贡献在火星大小的物体碰撞中特别重要，具有足够高的撞击能量，但仍然相对较低的重力。我们的研究结果清楚地表明，几次（打了就跑）碰撞的累积效应可以有效地剥离原行星的挥发层，特别是较小的天体，因为它可能很常见，例如，在拥有超级地球的系统中，一个精确的模型剥离挥发物，可以包括在未来的行星形成模拟必须考虑到打了就跑的事件和跟踪两个大的碰撞后碎片的成分变化的特点。
Collisions between large, similar-sized bodies are believed to shape the final characteristics and composition of terrestrial planets. Their inventories of volatiles such as water are either delivered or at least significantly modified by such events. Besides the transition from accretion to erosion with increasing impact velocity, similar-sized collisions can also result in hit-and-run outcomes for sufficiently oblique impact angles and large enough projectile-to-target mass ratios. We study volatile transfer and loss focusing on hit-and-run encounters by means of smooth particle hydrodynamics simulations, including all main parameters: impact velocity, impact angle, mass ratio and also the total colliding mass. We find a broad range of overall water losses, up to 75% in the most energetic hit-and-run events, and confirm the much more severe consequences for the smaller body also for stripping of volatile layers. Transfer of water between projectile and target inventories is found to be mostly rather inefficient, and final water contents are dominated by pre-collision inventories reduced by impact losses, for similar pre-collision water mass fractions. Comparison with our numerical results shows that current collision outcome models are not accurate enough to reliably predict these composition changes in hit-and-run events. To also account for non-mechanical losses, we estimate the amount of collisionally vaporized water over a broad range of masses and find that these contributions are particularly important in collisions of Mars-sized bodies, with sufficiently high impact energies, but still relatively low gravity. Our results clearly indicate that the cumulative effect of several (hit-and-run) collisions can efficiently strip protoplanets of their volatile layers, especially the smaller body, as it might be common, e.g., for Earth-mass planets in systems with Super-Earths. An accurate model for stripping of volatiles that can be included in future planet formation simulations has to account for the peculiarities of hit-and-run events and track compositional changes in both large post-collision fragments.
登录
查看更多内容
影响因子：
2.4
作者：
Holsapple, Keith A.
通讯作者：
Holsapple, Keith A.
影响因子：
4.9
作者：
Izidoro, A.;de Souza Torres, K.;Haghighipour, N.
通讯作者：
Haghighipour, N.
影响因子：
2.2
作者：
Collins, GS;Melosh, HJ;Ivanov, BA
通讯作者：
Ivanov, BA
影响因子：
2.4
作者：
Jutzi, Martin
通讯作者：
Jutzi, Martin
影响因子：
6.3
作者：
BENZ, W;ASPHAUG, E
通讯作者：
ASPHAUG, E