Earth's carbon deficit caused by early loss through irreversible sublimation

TL;DR

This paper suggests that early irreversible sublimation of carbon in the solar nebula led to Earth's significant carbon deficit, impacting its initial composition and organic inventory.

Contribution

It introduces a model linking early sublimation processes to Earth's carbon deficiency, supported by astronomical observations and geological constraints.

Findings

Sublimation front of carbon moved inward rapidly within the solar nebula.

Earth's precursor materials experienced substantial carbon loss due to sublimation.

Geological data confirms a severe carbon deficit in Earth's composition.

Abstract

Carbon is an essential element for life but its behavior during Earth's accretion is not well understood. Carbonaceous grains in meteoritic and cometary materials suggest that irreversible sublimation, and not condensation, governs carbon acquisition by terrestrial worlds. Through astronomical observations and modeling we show that the sublimation front of carbon carriers in the solar nebula, or the soot line, moved inward quickly so that carbon-rich ingredients would be available for accretion at 1 au after the first million years. On the other hand, geological constraints firmly establish a severe carbon deficit in Earth, requiring the destruction of inherited carbonaceous organics in the majority of its building blocks. The carbon-poor nature of the Earth thus implies carbon loss in its precursor material through sublimation within the first million years.