Very Deep Inside the SN 1987A Core Ejecta: Molecular Structures Seen in
  3D
  Most massive stars end their lives in core-collapse supernova explosions and
enrich the interstellar medium with explosively nucleosynthesized elements.
Following core collapse, the explosion is subject to instabilities as the shock
propagates outwards through the progenitor star. Observations of the
composition and structure of the innermost regions of a core-collapse supernova
provide a direct probe of the instabilities and nucleosynthetic products. SN
1987A in the Large Magellanic Cloud (LMC) is one of very few supernovae for
which the inner ejecta can be spatially resolved but are not yet strongly
affected by interaction with the surroundings. Our observations of SN 1987A
with the Atacama Large Millimeter/submillimeter Array (ALMA) are of the highest
resolution to date and reveal the detailed morphology of cold molecular gas in
the innermost regions of the remnant. The 3D distributions of carbon and
silicon monoxide (CO and SiO) emission differ, but both have a central deficit,
or torus-like distribution, possibly a result of radioactive heating during the
first weeks ("nickel heating"). The size scales of the clumpy distribution are
compared quantitatively to models, demonstrating how progenitor and explosion
physics can be constrained.
