arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1003.6077astro-ph.EP
收藏

木星上的深层水蒸发:来自热化学动力学和扩散模拟的新约束

The Deep Water Abundance on Jupiter: New Constraints from Thermochemical Kinetics and Diffusion Modeling

Channon Visscher, Julianne I. Moses, Sarah A. Saslow

摘要:

我们已经开发了一个一维的热化学动力学和扩散模型,木星的大气,准确地描述了从热化学制度在对流层深处(化学平衡建立)淬火制度在对流层上部(化学平衡被破坏)的过渡。该模型被用来计算对流层成分的化学丰度,并确定重要的化学途径CO-CH 4在氢占主导地位的大气中的相互转换。特别是,所观察到的摩尔分数和化学行为的CO是用来间接约束木星水库存。我们的模型可以重现观测到的对流层CO丰度,条件是木星对流层深层的水摩尔分数在(0.25-6.0)x 10^-3的范围内,相当于原太阳丰度的0.3 - 7.3倍(假设H2O/H2 = 9.61 x 10^-4)。我们的研究结果表明,木星的氧富集度大致类似于碳,氮和其他重元素,我们的结论是,可以排除需要非常大(>8倍太阳)的水富集的形成场景。我们还评估和完善简单的时间常数参数目前用于预测淬火的CO丰度木星,其他巨行星和褐矮星。

英文摘要:

We have developed a one-dimensional thermochemical kinetics and diffusion model for Jupiter's atmosphere that accurately describes the transition from the thermochemical regime in the deep troposphere (where chemical equilibrium is established) to the quenched regime in the upper troposphere (where chemical equilibrium is disrupted). The model is used to calculate chemical abundances of tropospheric constituents and to identify important chemical pathways for CO-CH4 interconversion in hydrogen-dominated atmospheres. In particular, the observed mole fraction and chemical behavior of CO is used to indirectly constrain the Jovian water inventory. Our model can reproduce the observed tropospheric CO abundance provided that the water mole fraction lies in the range (0.25-6.0) x 10^-3 in Jupiter's deep troposphere, corresponding to an enrichment of 0.3 to 7.3 times the protosolar abundance (assumed to be H2O/H2 = 9.61 x 10^-4). Our results suggest that Jupiter's oxygen enrichment is roughly similar to that for carbon, nitrogen, and other heavy elements, and we conclude that formation scenarios that require very large (>8 times solar) enrichments in water can be ruled out. We also evaluate and refine the simple time-constant arguments currently used to predict the quenched CO abundance on Jupiter, other giant planets, and brown dwarfs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑