Proton irradiation of Centaur, Kuiper Belt, and Oort Cloud objects at plasma to cosmic ray energy
Proton irradiation of Centaur, Kuiper Belt, and Oort Cloud objects at plasma to cosmic ray energy
复制标题
半人马座、柯伊伯带和奥尔特云天体在等离子体到宇宙射线能量下的质子辐照
DOI：
10.1023/b:moon.0000031944.41883.80
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发表时间：
2003-06-01
影响因子：
0.9
通讯作者：
Wang, C
中科院分区：
文献类型：
--
作者：
Cooper, JF;Christian, ER;Wang, C
等离子体和高能离子在半人马座、柯伊伯带和奥尔特云天体的冰冷表面上积累重要化学剂量的时间取决于日球层内外的照射位置。主要辐射成分包括太阳风等离子体离子，来自太阳紫外线电离的星际中性气体的吸收离子，由太阳和行星际激波加速的高能离子，包括假定的太阳风终止激波，以及来自局部星际介质（LISM）的银河系宇宙射线离子。我们给出了从航天器数据中得到的模型通量谱，以及40 AU的eV到GeV质子模型，85 AU的终止激波位置模型，以及LISM中的模型。在单位密度下，以小于1厘米的感表面深度为函数，根据光谱计算出每个分子累积剂量约为100 eV的年累积次数。Luu和Jewitt的碰撞重表面模型在等离子体、超热和高能质子的深度依赖剂量率的背景下被重新考虑，以及微流星体尘埃颗粒撞击造成的中度辐照的红色物质在高度辐照的中性物质的薄外壳下的全球暴露。这种材料应该在类似于40天文单位区域的动态“冷”物体上更明显。
Times for accumulation of chemically significant dosages on icy surfaces of Centaur, Kuiper Belt, and Oort Cloud objects from plasma and energetic ions depend on irradiation position within or outside the heliosphere. Principal irradiation components include solar wind plasma ions, pickup ions from solar UV ionization of interstellar neutral gas, energetic ions accelerated by solar and interplanetary shocks, including the putative solar wind termination shock, and galactic cosmic ray ions from the Local Interstellar Medium (LISM). We present model flux spectra derived from spacecraft data and models for eV to GeV protons at 40 AU, a termination shock position at 85 AU, and in the LISM. Times in years to accumulate dosages similar to 100 eV per molecule are computed from the spectra as functions of sensible surface depth less than one centimeter at unit density. The collisional resurfacing model of Luu and Jewitt is reconsidered in the context of depth-dependent dosage rates from plasma, suprathermal, and higher energy protons, and global exposure, by micrometeoroid dust grain impacts, of moderately irradiated red material below a thin crust of heavily irradiated neutral material. This material should be more visible on dynamically 'cold' objects in the similar to40 AU region.