  The porosity of an asteroid is important when studying the evolution of our
solar system through small bodies and for planning mitigation strategies to
avoid disasters due to asteroid impacts. Our knowledge of asteroid porosity
largely relies on meteorites sampled on Earth. However, chondrites sampled on
Earth are suggested to be sorted by strength. In this study, we obtained an
estimate of the most porous structure of primordial "granular" chondrite parent
bodies based on measurements of the compaction behavior of chondrite component
analogs. We measured compaction curves of dust and dust-bead mixture samples.
The dust sample consisted of various spherical and irregular particles with
diameters on the order of 10^0-10^1 $\mu$m. The mixture sample consisted of
dust and beads with different dust volume fractions (~0.2-1). We used 1.5 and
4.8 $\mu$m particles as dust as a first step, although the typical size of
materials in matrix may be much smaller. We approximated the compaction curve
of each sample with a power-law form and calculated the porosity structure of
the primordial chondrite parent bodies using the experimental results. Our
results show that the primordial parent bodies are likely to have higher
porosity than the chondrites. Moreover, the relatively higher volume fraction
of the matrix may be one of the reasons why most meteorites with high porosity
are carbonaceous chondrites.
