  Dust particles play a major role in the formation, evolution and chemistry of
interstellar clouds, stars and planetary systems. Commonly identified forms
include amorphous and crystalline carbon-rich particles and silicates. Also
present in many astrophysical environments are polycyclic aromatic hydrocarbons
(PAHs), detected through their infrared emission, and which are essentially
small flakes of graphene. Astronomical observations over the past four decades
have revealed a widespread unassigned Extended Red Emission (ERE) feature which
is attributed to luminescence of dust grains. Numerous potential carriers for
ERE have been proposed but none has gained general acceptance. In this Letter
it is shown that there is a strong similarity between laboratory optical
emission spectra of graphene oxide and ERE, leading to this proposal that
emission from graphene oxide nanoparticles is the origin of ERE and that these
are a significant component of interstellar dust. The proposal is supported by
infrared emission features detected by the Infrared Space Observatory (ISO) and
the Spitzer Space Telescope.
