v2.4.0

Earlier version of the analysis for Edwards (2026), "Constraints on the Origin of the Asteroid Belt's Compositional Gradient from Debiased Taxonomic Data", which cites v2.6.3. v2.5.0 redraws every figure at its printed size and adds four; its numbers are identical apart from a new block for the size-distance map (see its notes).

New robustness test: the X complex split by albedo. X-types are left out of both carbonaceous fractions, because without an albedo the X complex mixes enstatite-like, metallic and primitive bodies. By convention, an X-type with a measured albedo is classed by it: a P below p_V = 0.10, an M from 0.10 to 0.30, and an E above 0.30 (Fornasier, Clark & Dotto 2011, doi:10.1016/j.icarus.2011.04.022). The catalog's comp_class makes the same split. v2.4.0 applies it to classified X, Xc and the other X sub-classes; Xe and Xk are left alone because they already name their type. P-like bodies are counted with D/P, and they vote that way in their families. The results are in summary.json → x_split_by_albedo:

• 7,755 of the 13,763 classified X-types are split: 4,513 P, 2,960 M and 282 E.
• The broad fraction rises by at most 0.064.
• The narrow fraction C/(S+C) moves by at most 0.010, because 10 families change class.
• The P-like share of the split X-types is 0.38 in the inner belt and 0.54–0.66 beyond it.

Everything else is identical to v2.3.1. The new step runs after every bootstrap and draws no random numbers, so all seven figures and every other summary.json value are byte-identical. The input is still AsteroidCatalog data-2026-09-29c (data contract 1.8.1).

New API: catalog.split_x_by_albedo, gradient.zone_point, pipeline.x_split_by_albedo and config.X_SPLIT_ALBEDO.