Detection of the buckminsterfullerene cation (C60+) in space

TL;DR

This paper reports the first detection of the C60+ fullerene cation in space using infrared spectroscopy, supporting its role as a carrier of certain diffuse interstellar bands and confirming the presence of fullerenes in the interstellar medium.

Contribution

It provides the first gas-phase infrared detection of C60+ in space, combining observational, computational, and laboratory data to support its identification as a DIB carrier.

Findings

Detection of C60+ in the NGC 7023 nebula

Supports C60+ as a DIB carrier

Confirms existence of fullerenes in interstellar space

Abstract

In the early 90s, C60+ was proposed as the carrier of two diffuse interstellar bands (DIBs) at 957.7 and 963.2 nm, but a firm identification still awaits gas-phase spectroscopic data. Neutral C60, on the other hand, was recently detected through its infrared emission bands in the interstellar medium and evolved stars. In this contribution, we present the detection of C60+ through its infrared vibrational bands in the NGC 7023 nebula, based on spectroscopic observations with the Spitzer space telescope, quantum chemistry calculation, and laboratory data from the literature. This detection supports the idea that C60+ could be a DIB carrier, and provides robust evidence that fullerenes exist in the gas-phase in the interstellar medium. Modeling efforts to design specific observations, combined with new gas-phase data, will be essential to confirm this proposal. A definitive attribution of the 957.7 and 963.2 nm DIBs to C60+ would represent a significant step forward in the field.