Crystalline water ice on the Kuiper belt object (50000) Quaoar
Crystalline water ice on the Kuiper belt object (50000) Quaoar
复制标题
柯伊伯带天体上的结晶水冰 (50000) Quaoar
作者：
D. Jewitt;J. Luu
柯伊伯带是一个圆盘状的结构，由海王星以外绕太阳运行的固体组成。它是短周期彗星的来源，也可能是太阳系最原始物质的储存库。该带的表面温度很低（1050 K），这表明在形成时被捕获的冰应该在太阳系的年龄内被保存下来。不幸的是，大多数柯伊伯带天体都太暗了，即使用最大的望远镜也无法进行有意义的成分研究。据报道，水冰存在于少数物体中，但大多数看起来没有光谱特征。在这里，我们报告近红外观测大型柯伊伯带对象（50000）夸欧尔，揭示了结晶水冰和氨水合物的存在。结晶度表明冰已经被加热到至少110 K。氢氧化氨和结晶水冰都应该在大约107年的时间尺度上被高能粒子辐照破坏。我们的结论是，夸欧尔最近已重新露面，无论是以前埋（屏蔽）冰的影响暴露或冷火山放气，或这些过程的组合。
The Kuiper belt is a disk-like structure consisting of solid bodies orbiting the Sun beyond Neptune. It is the source of the short-period comets and the likely repository of the Solar System's most primitive materials. Surface temperatures in the belt are low (∼ 50 K), suggesting that ices trapped at formation should have been preserved over the age of the Solar System. Unfortunately, most Kuiper belt objects are too faint for meaningful compositional study, even with the largest available telescopes. Water ice has been reported in a handful of objects, but most appear spectrally featureless. Here we report near-infrared observations of the large Kuiper belt object (50000) Quaoar, which reveal the presence of crystalline water ice and ammonia hydrate. Crystallinity indicates that the ice has been heated to at least 110 K. Both ammonia hydrate and crystalline water ice should be destroyed by energetic particle irradiation on a timescale of about 107 yr. We conclude that Quaoar has been recently resurfaced, either by impact exposure of previously buried (shielded) ices or by cryovolcanic outgassing, or by a combination of these processes.