Solid-phase C_60 in the peculiar binary XX Oph?

TL;DR

This paper reports the first detection of solid-phase C_60 in the binary star XX Oph using infrared spectroscopy, suggesting its presence in circumstellar environments and excitation by hot stars.

Contribution

It provides the first evidence of solid C_60 in space and links its excitation to stars with specific effective temperatures.

Findings

Detection of solid C_60 in XX Oph

C_60 likely excited by stars with 15,000-30,000K

Solid C_60 may be common but often unnoticed

Abstract

We present infrared spectra of the binary XX Oph obtained with the Infrared Spectrograph on the Spitzer Space Telescope. The data show some evidence for the presence of solid C_60 - the first detection of C_60 in the solid phase - together with the well-known ``Unidentified Infrared'' emission features. We suggest that, in the case of XX Oph, the C_60 is located close to the hot component, and that in general it is preferentially excited by stars having effective temperatures in the range 15,000-30,000K. C_60 may be common in circumstellar environments, but un-noticed in the absence of a suitable exciting source.