German Aerospace Center, Institute of Planetary Research, Rutherfordstr. 2, 12489, Berlin, Germany.
Orig Life Evol Biosph. 2012 Jun;42(2-3):81-92. doi: 10.1007/s11084-012-9280-7. Epub 2012 May 30.
Water is essential for life. This is a trivial fact but has profound implications since the forming of life on the early Earth required water. The sources of water and the related amount of delivery depend not only on the conditions on the early Earth itself but also on the evolutionary history of the solar system. Thus we ask where and when water formed in the solar nebula-the precursor of the solar system. In this paper we explore the chemical mechanics for water formation and its expected abundance. This is achieved by studying the parental cloud core of the solar nebula and its gravitational collapse. We have identified two different sources of water for the region of Earth's accretion. The first being the sublimation of the icy mantles of dust grains formed in the parental cloud. The second source is located in the inner region of the collapsing cloud core - the so-called hot corino with a temperature of several hundred Kelvin. There, water is produced efficiently in the gas phase by reactions between neutral molecules. Additionally, we analyse the dependence of the production of water on the initial abundance ratio between carbon and oxygen.
水是生命所必需的。这是一个常识，但却有着深远的意义，因为早期地球上生命的形成需要水。水的来源和相关的输送量不仅取决于早期地球本身的条件，还取决于太阳系的演化历史。因此，我们要问水是在太阳系星云（太阳系的前身）的何处以及何时形成的。在本文中，我们探讨了水形成的化学力学及其预期丰度。这是通过研究太阳星云的原始云核及其引力塌缩来实现的。我们已经确定了地球吸积区的两个不同的水源。第一个是在原始云形成的尘埃冰幔的升华。第二个来源位于塌缩云核的内部区域，即所谓的热核，温度约为几百开尔文。在那里，通过中性分子之间的反应，水在气相中高效地产生。此外，我们还分析了水的产生对初始碳氧丰度比的依赖性。
