Are fulleranes responsible for the 21 micron feature?

Abstract

Recent detections of C${}_{60}$, C${}_{70}$, and C${}_{60}^{+}$ in space induced extensive studies of fullerene derivatives in circumstellar environments. As the promising fullerene sources, protoplanetary nebulae (PPNe) show a number of unidentified bands in their infrared spectra, among which a small sample exhibits an enigmatic feature at $\sim 21$\,$\mu$m. Hydrogenation of fullerenes can produce fulleranes emitting new infrared bands. In this paper, we investigate the possibility of fulleranes (C${}_{60}$H${}_m$) as the carrier of the 21\,$\mu$m feature in terms of theoretical vibrational spectra of fulleranes. The evidences favoring and disfavoring the fullerane hypothesis are presented. We made an initial guess for the hydrogen coverage of C${}_{60}$H${}_m$ that may contribute to the 21\,$\mu$m feature.

arXiv comment15 pages, 7 figures

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Cited by in corpus (2)

• Hydrogenated Fullerenes (Fulleranes) in Space
• Molecular gas in 21 and 30 micron sources: the 2\,mm and 1.3\,mm spectra of IRAS\,21318+5631 and 22272+5435