  Comets and chondrites show non-monotonic behaviour of their Deuterium to
Hydrogen (D/H) ratio as a function of their formation location from the Sun.
This is difficult to explain with a classical protoplanetary disk model that
has a decreasing temperature structure with radius from the Sun.
  We want to understand if a protoplanetary disc with a dead zone, a region of
zero or low turbulence, can explain the measured D/H values in comets and
chondrites.
  We use time snapshots of a vertically layered disk model with turbulent
surface layers and a dead zone at the midplane. The disc has a non-monotonic
temperature structure due to increased heating from self-gravity in the outer
parts of the dead zone. We couple this to a D/H ratio evolution model in order
to quantify the effect of such thermal profiles on D/H enrichment in the
nebula.
  We find that the local temperature peak in the disk can explain the diversity
in the D/H ratios of different chondritic families. This disk temperature
profile leads to a non-monotonic D/H enrichment evolution, allowing these
families to acquire their different D/H values while forming in close
proximity. The formation order we infer for these families is compatible with
that inferred from their water abundances. However, we find that even for very
young disks, the thermal profile reversal is too close to the Sun to be
relevant for comets.
