The interstellar chemistry of H2C3O isomers
  We present the detection of two H2C3O isomers, propynal and cyclopropenone,
toward various starless cores and molecular clouds, together with upper limits
for the third isomer propadienone. We review the processes controlling the
abundances of H2C3O isomers in interstellar media showing that the reactions
involved are gas-phase ones. We show that the abundances of these species are
controlled by kinetic rather than thermodynamic effects.
