Icy Grains from the Nucleus of Comet C/2013 US10 (Catalina)
Icy Grains from the Nucleus of Comet C/2013 US10 (Catalina)
复制标题
来自彗星 C/2013 US10（卡塔琳娜）核心的冰粒
DOI：
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发表时间：
2018
影响因子：
4.9
通讯作者：
J. Sunshine
中科院分区：
文献类型：
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作者：
S. Protopapa;M. Kelley;Bin Yang;J. Bauer;L. Kolokolova;C. Woodward;J. Keane;J. Sunshine
我们展示了红外望远镜设施/SpeX 和 NEOWISE 对动态新彗星 C/2013 US10（卡塔琳娜）（以下简称 US10）的观测，从 5.8 个天文单位入站，到近日点附近 1.3 个天文单位，然后回到 5.0 个天文单位出站。我们在 US10 的彗发中检测到水冰，评估和监测冰的物理特性，因为日照随日心距离变化，并研究水冰和二氧化碳之间的关系。这组测量在轨道覆盖范围上是独一无二的，可用于推断冰的物理演化，以及可能的核成分。我们报告了（1）在-5.8 au、-5.0 au、+3.9 au（其中<0 au表示近日点前历元）的慧发的近红外光谱测量，所有这些都呈现出水冰粒的证据，（2）在1.3和2.3 au处以尘埃为主的彗差，（3）CO2/Afρ比率从-4.9增加到1.8 个单位。我们认为，高挥发性二氧化碳的升华是将水冰粒拖入整个轨道的彗发的原因。一旦进入昏迷状态，水冰粒的可观测性就受到冰粒升华寿命的控制，这似乎需要一些小的灰尘污染物（即非纯冰粒）。在 时，冰粒的寿命很长，并且可能自从离开彗核后就没有变化。我们发现 US10 彗星的核心由约 1 μm 的水冰粒和其他成分组成，其中含有高达 1% 的耐火材料。
We present Infrared Telescope Facility/SpeX and NEOWISE observations of the dynamically new comet C/2013 US10 (Catalina), hereafter US10, from 5.8 au inbound, to near perihelion at 1.3 au, and back to 5.0 au outbound. We detect water ice in the coma of US10, assess and monitor the physical properties of the ice as insolation varies with heliocentric distance, and investigate the relationship between water ice and CO2. This set of measurements is unique in orbital coverage and can be used to infer both the physical evolution of the ice, and, potentially, the nucleus composition. We report (1) nearly identical near-infrared spectroscopic measurements of the coma at −5.8 au, −5.0 au, +3.9 au (where <0 au indicates pre-perihelion epochs), all presenting evidence of water-ice grains, (2) a dust-dominated coma at 1.3 and 2.3 au and, (3) an increasing CO2/Afρ ratio from −4.9 to 1.8 au. We propose that sublimation of the hyper-volatile CO2 is responsible for dragging water-ice grains into the coma throughout the orbit. Once in the coma, the observability of the water-ice grains is controlled by the ice grain sublimation lifetime, which seems to require some small dust contaminant (i.e., non-pure ice grains). At , the ice grains are long-lived and may be unchanged since leaving the comet nucleus. We find that the nucleus of comet US10 is made of, among other components, ∼1 μm water-ice grains containing up to 1% refractory materials.