The Solar Nebula on Fire: A Solution to the Carbon Deficit in the Inner Solar System

TL;DR

This paper proposes that primordial carbon grains in the early Solar Nebula were destroyed by oxygen atoms heated by stellar accretion, explaining the observed carbon deficiency in Earth, meteorites, and other planetary systems.

Contribution

It introduces a novel mechanism where stellar accretion heating causes preferential destruction of carbon grains in the inner Solar System.

Findings

Primordial carbon grains are destroyed within 5 AU due to stellar accretion heating.

This process explains the carbon deficiency observed in Earth and meteorites.

The mechanism accounts for the compositional gradient in the asteroid belt.

Abstract

Despite a surface dominated by carbon-based life, the bulk composition of the Earth is dramatically carbon poor when compared to the material available at formation. Bulk carbon deficiency extends into the asteroid belt representing a fossil record of the conditions under which planets are born. The initial steps of planet formation involve the growth of primitive sub-micron silicate and carbon grains in the Solar Nebula. We present a solution wherein primordial carbon grains are preferentially destroyed by oxygen atoms ignited by heating due to stellar accretion at radii < 5 AU. This solution can account for the bulk carbon deficiency in the Earth and meteorites, the compositional gradient within the asteroid belt, and for growing evidence for similar carbon deficiency in rocks surrounding other stars.