Discovery of Fullerenes in the shell of candidate Luminous Blue Variable WRAY 16-232

Abstract We report the discovery of fullerene in the circumstellar environment of WRAY 16-232, a strong candidate luminous blue variable. Multiple pointings of archival Spitzer IRS spectra reveal, for the first time, the presence of prominent vibrational bands of C60 at 17.4 and 18.9 $\mu$m in an LBV envelope, along with the strong polycyclic aromatic hydrocarbon features. These observations suggest that, despite the harsh radiative conditions, large carbonaceous molecules can form, process and survive in the ejecta of massive stars. Complementary optical spectroscopy with SALT HRS shows multiple P Cygni profiles in Hα, He i, and Fe ii lines, which are indicative of a dense, expanding wind and substantial mass loss. Furthermore, analysis of decade long photometric data shows short-term brightness variations of ∼ 0.5 mag. These results not only reinforce the classification of WRAY 16-232 as a strong LBV candidate but also provide new insights into the mechanisms of dust formation and the chemical enrichment of the interstellar medium by massive stars. We discuss various scenarios for fullerene formation in such environments, and find that shock processing due to wind-wind interactions could be playing a vital role. The shell of WRAY 16-232 has an ideal UV field strength and the time scales appears to match with shock processing timescales. The results highlight the need for further high spatial/spectral resolution and temporal observations to confirm the formation and survival scenario of C60 in its shell.