Hunting for hot corinos and WCCC sources in the OMC-2/3 filament
  Context: Solar-like protostars are known to be chemically rich, but it is not
yet clear how much their chemical composition can vary and why. So far, two
chemically distinct types of Solar-like protostars have been identified: hot
corinos, which are enriched in interstellar Complex Organic Molecules (iCOMs),
such as methanol (CH$_3$OH) or dimethyl ether (CH$_3$OCH$_3$), and Warm Carbon
Chain Chemistry (WCCC) objects, which are enriched in carbon chain molecules,
such as butadiynyl (C$_4$H) or ethynyl radical (CCH). However, none of these
have been studied so far in environments similar to that in which our Sun was
born, that is, one that is close to massive stars. Aims: In this work, we
search for hot corinos and WCCC objects in the closest analogue to the Sun's
birth environment, the Orion Molecular Cloud 2/3 (OMC-2/3) filament located in
the Orion A molecular cloud. Methods: We obtained single-dish observations of
CCH and CH$_3$OH line emission towards nine Solar-like protostars in this
region. As in other, similar studies of late, we used the [CCH]/[CH$_3$OH]
abundance ratio in order to determine the chemical nature of our protostar
sample. Results: Unexpectedly, we found that the observed methanol and ethynyl
radical emission (over a few thousands au scale) does not seem to originate
from the protostars but rather from the parental cloud and its
photo-dissociation region, illuminated by the OB stars of the region.
Conclusions: Our results strongly suggest that caution should be taken before
using [CCH]/[CH$_3$OH] from single-dish observations as an indicator of the
protostellar chemical nature and that there is a need for other tracers or high
angular resolution observations for probing the inner protostellar layers.
