Modeling the Jovian subnebula. II. Composition of regular satellite ices
Modeling the Jovian subnebula. II. Composition of regular satellite ices
复制标题
模拟木星亚星云。
DOI：
10.1051/0004-6361:20053211
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发表时间：
2005
影响因子：
6.5
通讯作者：
Y. Alibert
中科院分区：
文献类型：
--
作者：
O. Mousis;Y. Alibert
我们使用木星的亚星云的演化湍流模型来约束其定期冰卫星的冰组成。我们认为CO2、CO、CH4、N2、NH3、H2S、Ar、Kr和H2O是太阳星云气相中的主要挥发组分。除CO2结晶为纯冷凝物外，所有这些挥发性物质都被H2O捕获，形成太阳星云中的水合物或笼形水合物。一旦凝结，这些冰被合并到原始木星的喂养区产生的不断增长的星子中。其中一些固体从太阳星云流到亚星云，可能是被正在形成的木星规则卫星吸积的。我们发现，冰嵌入固体进入早期时代的木星subdisk都蒸发。这使我们考虑两种不同的情况下，定期冰卫星形成，以估计其所包含的冰的成分。在第一种情况下，冰冷的卫星是从木星的喂养区产生的星子中吸积而没有进一步蒸发，而在第二种情况下，冰冷的卫星是从木星亚星云中产生的星子中吸积而成。在后一种情况下，我们研究了木星亚星云中碳和氮的气相化学的演变，我们发现，N2到NH3，CO到CO 2，CO到CH 4的转换都被抑制在主要部分的subdisk。最后，我们评估的质量丰度的主要挥发性物种相对于H2 O在木星定期冰卫星的内部。然后，我们的研究结果是兼容的检测的CO2表面上的木卫四和木卫三，并与存在的NH 3设想在地下海洋内木卫三和木卫四。
We use an evolutionary turbulent model of Jupiter's subnebula to constrain the composition of ices incorporated in its regular icy satellites. We consider CO 2 , CO, CH 4 , N 2 , NH 3 , H 2 S, Ar, Kr and Xe as the major volatile species existing in the gas-phase of the solar nebula. All these volatile species, except CO 2 which crystallized as a pure condensate, are assumed to be trapped by H 2 O to form hydrates or clathrate hydrates in the solar nebula. Once condensed, these ices were incorporated into the growing planetesimals produced in the feeding zone of proto-Jupiter. Some of these solids then flowed from the solar nebula to the subnebula, and may have been accreted by the forming Jovian regular satellites. We show that ices embedded in solids entering at early epochs into the Jovian subdisk were all vaporized. This leads us to consider two different scenarios of regular icy satellite formation in order to estimate the composition of the ices they contain. In the first scenario, icy satellites were accreted from planetesimals that have been produced in Jupiter's feeding zone without further vaporization, whereas, in the second scenario, icy satellites were accreted from planetesimals produced in the Jovian subnebula. In this latter case, we study the evolution of carbon and nitrogen gas-phase chemistries in the Jovian subnebula and we show that the conversions of N 2 to NH 3 , of CO to CO 2 , and of CO to CH 4 were all inhibited in the major part of the subdisk. Finally, we assess the mass abundances of the major volatile species with respect to H 2 O in the interiors of the Jovian regular icy satellites. Our results are then compatible with the detection of CO 2 on the surfaces of Callisto and Ganymede and with the presence of NH 3 envisaged in subsurface oceans within Ganymede and Callisto.