Vol. 606
In section 10. Planets and planetary systems

Spatial distribution of carbon dust in the early solar nebula and the carbon content of planetesimals

The outer solar system, as sampled by comets and interplanetary dust particles (IDPs), appears to be rich in carbon. So is the interstellar medium and the Sun itself. On the other hand, analysis of the composition of meteorites and terrestrial planets shows that the inner solar system is severely depleted in carbon (by 99.9% in the case of the Earth). Gail & Trieloff study the fate of carbon-bearing species as they drifted from the outer to the inner solar system during the protosolar disk phase. They find that the complex hydrocarbon components of carbonaceous material are vaporized at temperatures between 250 and 400 K, but that the amorphous carbon component survives to temperatures of 1 200 K. They conclude that grains in the protosolar disk must have experienced these kind of high temperatures and infer that flash heating associated with chondrule formation was key to the removal of carbon in the inner solar system.