Organic chemistry in the protosolar analogue HOPS-108: Environment
  matters
  Hot corinos are compact regions around solar-mass protostellar objects that
are very rich in interstellar complex organic molecules (iCOMs). They are
believed to represent the very early phases of our Solar System's birth, which
was very likely also characterized by rich organic chemistry. While most of the
studied hot corinos are either isolated or born in a loose protocluster, our
Sun was born in a densely packed star cluster, near massive stars whose
ultraviolet radiation must have contributed to shaping the evolution of the
surrounding environment. In addition, internal irradiation from energetic
particles ($>$10 Mev), whose imprint is seen today in the products of
short-lived radionuclides in meteoritic material, is also known to have
occurred during the Solar System formation. How did all these conditions affect
the chemistry of the proto-Sun and its surroundings is still an open question.
To answer this question, we studied HOPS-108, the hot corino located in the
protosolar analogue OMC-2 FIR4. The study was carried out with ALMA at 1.3mm
with an angular resolution of $\sim$100 AU. We detected 11 iCOMs such as
CH$_{3}$OH HCOOCH$_{3}$ and CH$_{3}$OCH$_{3}$. Our results can be summarized as
follows: (1) an enhancement of HCOOCH3 with respect to other hot corinos, (2) a
[CH$_{3}$OCH$_{3}$]/[HCOOCH$_{3}$] abundance ratio of $\sim$0.2 marginally
deviating from the usual trend seen in other sources
([CH$_{3}$OCH$_{3}$]/[HCOOCH$_{3}$] $\sim$1), (3) a [CH$_{2}$DOH]/[CH$_{3}$OH]
ratio of 2.5\% which is lower than what is seen in Perseus and Ophiuchus hot
corinos ($\sim$7\%-9\%) and similar to that seen in HH212 another source
located in Orion. This might result from different physical conditions in the
Orion molecular complex compared to other regions.
