The "inherited" organic inventory of (exo)planets

I will review our understanding of the composition of planets that form within the inner few au of their host stars. We focus in particular on the supply of refractory carbon to terrestrial worlds, from Earth-like to super-Earths and sub-Neptunes. This refractory carbon is inherited from the interstellar medium and is supplied with water ice. For many planetary systems, including our Solar System, the water ice line, or ice sublimation front, within the planet-forming disk has long been a key focal point, representing the boundary between where water-rich and water-poor planets would form. We posit that the soot line, the location inside of which solid-state organics are irreversibly destroyed, is also a key location within a planet forming disk. The soot line is closer to the host star than the water snow line and overlaps with the location of the majority of detected exoplanets. Based on this concept we predict a population of planets will form on short-period orbits with significant inventories of organics but low amounts of water. As a result, the mantle of such a planet could be rich in reduced carbon but have relatively low oxygen (water) content. Outgassing would naturally yield the ingredients for haze production, which is widely observed in sub-Neptune-sized exoplanets. Although this type of planet has no solar system counterpart, it should be common in the galaxy.