  It has been suggested that shock waves in the solar nebula formed the high
temperature materials observed in meteorites and comets. It is shown that the
temperatures at the inner rim of the solar nebula could have been high enough
over a sufficient length of time to produce chondrules, CAIs, refractory dust
grains and other high-temperature materials observed in comets and meteorites.
  The solar bipolar jet flow may have produced an enrichment of 16O in the
solar nebula over time and the chondrule oxygen isotopic reservoirs are
possibly due to temporal changes in the relative position of the inner edge of
the solar nebula and the subsequent strength of the solar bipolar jet flow. As
such, nebula heating models, such as the shock model, are not required to
explain the formation of most high-temperature chondritic components
