Experimental study on the chemical strucutre of the Jovian planets and their satellistes

木星行星及其卫星化学结构的实验研究

• 批准号: 61540595
• 负责人: OHTANI Eiji
• 金额: $ 1.66万
• 依托单位: Ehime University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61540595/
• 关键词: Jovian Planets; Satellite; chemical structure; water-ammonia system; phase relation; diamond anvil cell; 高圧; 水; アンモニア; 圧力; 相関係

We have studied the phase relation of H_2O-NH_3 system up to 10 GPa by using the diamond anvil cell, in order to understand the chemical structure of icy satellites of the Jovian Planets. The starting materials were the aqueous ammonia solutions containing ammonia up to 26.8 wt%. Determination of the phase relations was conducted by microscopic observation of the sample at high pressure, while identification of the phases was made by in situ X-ray diffraction at high pressure.The pressure of the liquidus in the H_2O-14wt%NH_3 composition, which is the composition of the cosmic ratio of H_2O and NH_3, was 1.2 Gpa at 295 K, where Ice VI begins to crystallize as the liquidus phase. The solidus locates at around 2 GPa at 295 GPa, where Ice VI and an ammonia hydrate are stable. The ammonia hydrate seems to transform into unknown phase at around 4 GPa at 295 K. The structures of the unknown ammonia hydrates are not identified due to lack of quality of the X-ray diffraction data.On the basis of the present results, the estimated temperature distributions in the icy satellites, and the density relationship between polymorphs of ice and the aqueous ammonia solution, it is suggested that the ammonia enriched liquid formed by partial melting in the interior of the satellites tends to move upwards and to disperse into the space. Thus highly volatile components such as NH_3 could be depleted in the present icy satellites of the Jovian Planets.

我们利用金刚石砧室研究了高达10 GPa的H_2O-NH_3体系的相关系，以了解木星冰冷卫星的化学结构。起始原料是含有高达26.8wt%氨的氨水溶液。通过高压下对样品进行显微观察来确定相关系，并通过高压下原位X射线衍射来进行物相的鉴定。H_2O-14wt%NH_3组合物中的液相线压力为是H_2O和NH_3的宇宙比组成，在295 K时为1.2 Gpa，其中Ice VI开始结晶为液相。固相线位于 295 GPa 处约 2 GPa，此处 Ice VI 和氨水合物是稳定的。氨水合物似乎在 295 K、4 GPa 左右转变成未知相。由于缺乏 X 射线衍射数据的质量，未知氨水合物的结构尚未确定。根据目前的结果，估计冰卫星中的温度分布以及冰多晶型物与氨水溶液之间的密度关系表明，卫星内部部分熔化形成的富氨液体倾向于向上移动并扩散到卫星内部。 空间。因此，诸如 NH_3 之类的高度挥发性成分可能会在木星行星目前的冰冷卫星中耗尽。