Fullerenes in Circumstellar and Interstellar Environments

In recent years, the fullerene species C₆₀ (and to a lesser extent also C₇₀) has been reported in the mid-IR spectra of various astronomical objects. Cosmic fullerenes form in the circumstellar material of evolved stars, and survive in the interstellar medium (ISM). It is not entirely clear how they form or what their excitation mechanism is.