Growth of planetesimals by impacts at ∼25 m/s
Growth of planetesimals by impacts at ∼25 m/s
复制标题
星子因约 25 m/s 的撞击而增长
DOI：
10.1016/j.icarus.2005.04.002
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发表时间：
2005
期刊：
影响因子：
3.2
通讯作者：
O. Krauss
中科院分区：
文献类型：
--
作者：
G. Wurm;G. Paraskov;O. Krauss
本文研究了毫米级尘埃弹与厘米级尘埃靶的中心碰撞实验。目标和弹丸是由微米级SiO2颗粒组成的粉尘聚集体。碰撞速度可达25 m/s。碰撞的一般结果在很大程度上取决于撞击速度。对于低于13米/秒的碰撞，会发生反弹和小程度的碎裂。然而，在高达25 m/s的较高碰撞速度下，碰撞后约50%的射弹质量刚性地粘在目标上。因此，物体的净增长在高速碰撞中是可能的。这支持了这样一种观点，即通过碰撞生长的星子形成是一个可行的机制，在较高的冲击速度。在我们设定的参数范围内，实验甚至表明，更高的撞击速度可能有利于尘埃体之间碰撞的增长。在最高的撞击速度下，大多数喷出物都是大小约为500微米的小尘埃聚集体。详细地说，对于小于500 μm的非常小的粒子，喷出的尘埃聚集体的尺寸分布是平坦的，而对于较大的喷出尘埃聚集体则遵循幂律，幂为−5.6±0.2。在约1 mm的尺寸处有一个尖锐的上截止点，只有少数颗粒稍大。喷射角相对于目标表面小于3°。这些快速喷出物以撞击速度的40±10%移动。
We study central collisions between millimeter-sized dust projectiles and centimeter-sized dust targets in impact experiments. Target and projectile are dust aggregates consisting of micrometer-sized SiO2particles. Collision velocities range up to 25 m/s. The general outcome of a collision strongly depends on the impact velocity. For collisions below 13 m/s rebound and a small degree of fragmentation occur. However, at higher collision velocities up to 25 m/s approximately 50% of the mass of the projectile rigidly sticks to the target after the collision. Thus, net growth of a body is possible in high speed collisions. This supports the idea that planetesimal formation via collisional growth is a viable mechanism at higher impact velocities. Within our set of parameters the experiments even suggest that higher impact velocities might be preferable for growth in collisions between dusty bodies. For the highest impact velocities most of the ejecta is within small dust aggregates about 500 μm in size. In detail the size distribution of ejected dust aggregates is flat for very small particles smaller than 500 μm and follows a power law for larger ejected dust aggregates with a power of −5.6±0.2. There is a sharp upper cut-off at about 1 mm in size with only a few particles being slightly larger. The ejection angle is smaller than 3° with respect to the target surface. These fast ejecta move with 40±10% of the impact velocity.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell