Mass sufficiency of unmelted early NC planetesimals

Determine whether early-generation, small NC planetesimals that escaped melting and differentiation carried sufficient mass to serve as the precursors of the NC chondrites.

Background

The paper argues that efficient isolation of the NC reservoir from inward-drifting CC dust implies that the inner disk was not substantially replenished during late stages. This raises the problem of how enough primitive dust remained available to form the late-accreting NC chondrite parent bodies.

The authors consider an origin in secondary dust generated by collisions among earlier planetesimals, but regard this as unlikely because NC chondrites preserve presolar grains and isotopic heterogeneity. They therefore identify early, small planetesimals that escaped melting and differentiation as a possible source, while explicitly leaving unresolved whether such bodies contained enough mass.