• Formed in the low densities of space from large polycyclic aromatic hydrocarbons (PAHs), usually C₆₆H₂₀. This process is caused by the irradiation of the PAHs by ultraviolet photons which results in dehydrogenation until a C₆₀ fullerene is formed.

References

Berné, O., Montillaud, J. and Joblin, C. (2015). Top-down formation of fullerenes in the interstellar medium. Astronomy & Astrophysics, 577, p.A133. doi:https://doi.org/10.1051/0004-6361/201425338.(Accessed: 20 March 2025).