Ingredients for Solar-like Systems: protostar IRAS 16293-2422 B versus
  comet 67P/Churyumov-Gerasimenko
  Our modern day Solar System has $4.6\times10^9$ yrs of evolution behind it
with just a few relics of its birth conditions remaining. Comets are thought to
be some of the most pristine tracers of the initial ingredients that were
combined to produce the Earth and the other planets. Other low-mass protostars
may be analogous to our proto-Sun and hence, could be used to study the
building blocks necessary to form Solar-like systems. This study tests this
idea on the basis of new high sensitivity, high spatial resolution ALMA data on
the protoplanetary disc-scales (~70 au) of IRAS 16293-2422 and the bulk
composition of comet 67P/Churyumov-Gerasimenko, as determined for the first
time with the unique in situ monitoring carried out by Rosetta. The comparative
analysis of the observations from the Protostellar Interferometric Line Survey
(PILS) and the measurements made with Rosetta Orbiter Spectrometer for Ion and
Neutral Analysis (ROSINA) shows that the relative abundances of CHO-, N-, and
S-bearing molecules correlate, with some scatter, between protostellar and
cometary data. A tentative correlation is seen for the first time for P- and
Cl-bearing compounds. The results imply that the volatile composition of
cometesimals and planetesimals is partially inherited from the pre- and
protostellar phases of evolution.
