论文标题

错位的环形磁盘是星际小行星的有效祖细胞

Misaligned circumbinary disks as efficient progenitors of interstellar asteroids

论文作者

Childs, Anna C., Martin, Rebecca G.

论文摘要

高度倾向于二元轨道的气态环盘(CBD)通常在自然界中观察到。这些磁盘含有颗粒,一旦气盘消散,由于节点进动,它们可以达到大型相互倾斜。通过包括碎片化的N体模拟,我们证明了颗粒的未对准磁盘可能是星际小行星(ISA)的有效祖细胞。在具有较大相互倾斜的颗粒之间发生的碰撞具有较大的冲击速度,可能导致质量射出,并具有各种碎片大小和射血速度。我们探索了大多数陆地行星形成材料的二进制参数,而不是积聚到行星中。射出大量材料所需的未对准会随二元偏心率降低。如果二进制偏心率的分布是均匀的,并且相对于二进制轨道的初始粒子CBD方向是各向同性的,则大约59%的二进制文件更有可能通过高速速率碰撞的高速度碰撞而不是维持这种材料,而不是维持地面行星。但是,在气盘相中与非零磁盘粘度的二进制 - 磁盘相互作用将减少该部分。 Oumuamua的组成,小尺寸,高度细长的形状和翻滚运动与未对准的CBD产生的ISA一致。

Gaseous circumbinary disks (CBDs) that are highly inclined to the binary orbit are commonly observed in nature. These disks harbor particles that can reach large mutual inclinations as a result of nodal precession once the gas disk has dissipated. With n-body simulations that include fragmentation we demonstrate that misaligned disks of particles can be efficient progenitors of interstellar asteroids (ISAs). Collisions that take place between particles with large mutual inclinations have large impact velocities which can result in mass ejection, with a wide range of fragment sizes and ejection velocities. We explore the binary parameters for which the majority of the terrestrial planet forming material is ejected rather than accreted into planets. The misalignment required to eject significant material decreases with binary eccentricity. If the distribution of binary eccentricity is uniform and the initial particle CBD orientation relative to the binary orbit is isotropic, about 59% of binaries are more likely to eject the majority of their CBD terrestrial planet disk mass through high velocity body-body collisions rather than retain this material and build terrestrial planets. However, binary--disk interactions during the gas disk phase with non-zero disk viscosity will reduce this fraction. The composition, small size, highly elongated shape, and tumbling motion of `Oumuamua is consistent with ISAs generated by misaligned CBDs.

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