Hydrogen core composition

Figure 2. Overview of the hydrogen isotopic compositions of different objects, materials, and reservoirs in the solar system and beyond. The data are discnssed in different portions of this review paper, and most are snmmarized in tabnlar form in the recent review of Robert et al. (2000). Points with error bars represent single valnes with a quoted imcertainty. Solid bars reflect the range of multiple measurements ( 10 or more of analyses in most cases). The two astronomical settings are cold, dense interstellar clouds (T 10 K) and so-called hot cores, such as found in Orion, where temperatures are 70K and above. Behind the data for solar system objects lies much complexity which cannot be represented on a single summary figure. For example, even though the range of D/H in water from bulk chondrites is relatively large, most of the samples fall in a very narrow range, as described in the text.

Figure 2.41. Raw data of core level spectra of an activation experiment of catalyst 2 in static hydrogen. The compositions were derived from integration of the Fe 2p and O Is core level spectra. No significant difference in the Fe 0 ratios was obtained if the Fe 3p core level spectra were used indicating a largely correct background subtraction (analyzer mode FAT 50 eV).

In the region of the terrestrial planets, there may have been several thousand planetesimals of up to several hundred kilometres in diameter. During about ten million years, these united to form the four planets—Mercury, Venus, Earth and Mars—which are close to the sun. Far outside the orbit of the planet Mars, the heavier planets were formed, in particular Jupiter and Saturn, the huge masses of which attracted all the hydrogen and helium around them. Apart from their cores, these planets have a similar composition to that of the sun. Between the planets Mars and Jupiter, there is a large zone which should really contain another planet. It... 

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