THE FORMATION OF THE COLLISIONAL FAMILY AROUND THE DWARF PLANET HAUMEA
THE FORMATION OF THE COLLISIONAL FAMILY AROUND THE DWARF PLANET HAUMEA
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DOI：
10.1088/0004-637x/714/2/1789
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发表时间：
2010-05-10
影响因子：
4.9
通讯作者：
Stewart, Sarah T.
中科院分区：
文献类型：
--
作者：
Leinhardt, Zoe E. M.;Marcus, Robert A.;Stewart, Sarah T.
妊神星是一颗快速旋转的细长矮行星（直径约1500公里），有两颗卫星，与轨道相似的几个较小的柯伊伯带天体（KBO）“家族”有关。妊神星系统的所有成员都有一个水冰的光谱特征，这一特征与所有其他KBO都不同。妊神星家族成员之间的相对速度太小，不可能是由一个大型前体的灾难性分裂形成的，这是在主带中围绕小得多的小行星形成家族的过程。在这里，我们展示了妊神星系统的所有不寻常的特征都可以用一种新型的巨大碰撞来解释：两个巨大天体之间的擦撞和合并碰撞。擦肩而过的碰撞产生了很高的角动量，从细长的合并体的冰壳中剥离出碎片。这些碎片变成了卫星和家庭成员。巨型碰撞的结果对撞击参数极为敏感。与主带相比，柯伊伯带中最大的天体质量更大，碰撞速度更慢;因此，太阳系内外的巨型碰撞结果截然不同。柯伊伯带中的矮行星记录了出乎意料的大量巨型碰撞，这需要在太阳系形成末期发生特殊的动力学事件。
Haumea, a rapidly rotating elongated dwarf planet (similar to 1500 km in diameter), has two satellites and is associated with a "family" of several smaller Kuiper Belt objects (KBOs) in similar orbits. All members of the Haumea system share a water ice spectral feature that is distinct from all other KBOs. The relative velocities between the Haumea family members are too small to have formed by catastrophic disruption of a large precursor body, which is the process that formed families around much smaller asteroids in the main belt. Here, we show that all of the unusual characteristics of the Haumea system are explained by a novel type of giant collision: a graze and merge impact between two comparably sized bodies. The grazing encounter imparted the high angular momentum that spun off fragments from the icy crust of the elongated merged body. The fragments became satellites and family members. Giant collision outcomes are extremely sensitive to the impact parameters. Compared to the main belt, the largest bodies in the Kuiper Belt are more massive and experience slower velocity collisions; hence, outcomes of giant collisions are dramatically different between the inner and outer solar system. The dwarf planets in the Kuiper Belt record an unexpectedly large number of giant collisions, requiring a special dynamical event at the end of solar system formation.