How might carbon move before rocky planets form?

What the spectrum shows

JWST’s MIRI instrument measured molecular absorption toward the young protostar HOPS-68. Fitting gas-layer models to the spectrum yields temperatures; spatial locations remain inferred.[1]

Warm hydrogen cyanide and acetylene, about 319–432 K and blueshifted (shifted to shorter wavelengths), are linked to a possible wind base. Cooler molecules near 40 K are associated with the outer disk, envelope or cavity; these locations are inferred, not mapped.[1]

A proposed route

The authors propose refractory (heat-resistant) carbon-bearing grains release gas in a 500–1,200 K inner zone. A wind could carry some outward, where ultraviolet chemistry may build longer chains. The zone itself is not mapped.[1]

Planetary context and limits

Earth is carbon-poor compared with primitive solar-system material. Li and colleagues’ 2021 solar-nebula model places the soot line near 500 K, where heat-resistant carbon carriers turn mainly into gas. The mechanism applies to material heated inside that boundary; the authors discuss other loss processes too.[2]

The HOPS paper studies one object and leaves wind carbon loss unquantified. Li and colleagues model the early Solar System; neither study establishes a direct connection between the HOPS-68 wind and Earth’s carbon deficit.[1][2]