  We present the detection of fullerenes C60 and C70 in the star-forming region
IC 348 of the Perseus molecular cloud. Mid-IR vibrational transitions of C60
and C70 in emission are found in Spitzer IRS spectra of individual stars (LRLL
1, 2, 58), in the averaged spectrum of three other cluster stars (LRLL 21, 31
and 67) and in spectra obtained at four interstellar locations distributed
across the IC 348 region. Fullerene bands appear widely distributed in this
region with higher strength in the lines-of-sight of stars at the core of the
cluster. Emission features consistent with three most intense bands of the
C_{60}^+ and with one of C_{60}^- are also found in several spectra, and if
ascribed to these ionized species it would imply ionization fractions at 20 and
10 %, respectively. The stars under consideration host protoplanetary disks,
however the spatial resolution of the spectra is not sufficient to disentangle
the presence of fullerenes in them. If fullerene abundances in the cloud were
representative of IC 348 protoplanetary disks, C60, the most abundant of the
two species, could host 0.1 % of the total available carbon in the disks. This
should encourage dedicated searches in young disks with upcoming facilities as
JWST. Fullerenes provide a reservoir of pentagonal and hexagonal carbon rings
which could be important as building blocks of prebiotic molecules. Accretion
of these robust molecules in early phases of planet formation may contribute to
the formation of complex organic molecules in young planets.
