Planetesimals

ξ	accretion efficiency, (MF-M1)/M2 ≤ 1
SSC	Similar Sized Collision, R1 ~ R2, vrel ~ vesc
HRC	Hit and Run Collision, ξ ~ 0
NLB	Next largest contributor bodies
GMC	graze-and-merge collions, ξ → 1
SFD	size frequency distribution dn ~ R(-α) dR
γ	Normalized projectile mass ( M2/(M1+M2)
θ	Impact angle asin(b/R1+R2)
b	impact parameter, closest radial distance

This is mostly about the formation of planets from planetesimals,

p11 Walsh 2011 Vesta and Ceres (remaining oligarchs) are the last of hundreds >99% ejected by resonant scattering.
p11 we know of metallic cores from small satellites, most core compositions unknown
p11 planetesmals > 100-200 km immune to impact disruption
p22 iron droplets can rain out on a Stokes timescale ~ R η / g r2 Δ ρ η matrix viscosity in poises
p40 Fig 3.1 Estimated values of present dayt asteroid belt from Bottke et al (2005b) "Linking ... " Icarus 179, 63-94
- cumulative log-log plot, vaguely straight lines

p71 Enstatite meteorites: E-type, 2% of falls, rare, 200 known, parent body Psyche, reduced, metal or sulphide not oxide, MgSiO₂