diff --git a/wizard-work/ledger/planets.csv b/wizard-work/ledger/planets.csv
new file mode 100644
index 0000000..f0e3950
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+++ b/wizard-work/ledger/planets.csv
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+name,order,category,mean_distance_km,eq_radius_km,orbital_period_yr
+Mercury,1,terrestrial,57909175,2439.64,0.2408467
+Venus,2,terrestrial,108208930,6051.59,0.61519726
+Earth,3,terrestrial,149597890,6378.1,1.0000174
+Mars,4,terrestrial,227936640,3397.00,1.8808476
+Jupiter,5,gas giant,778412010,71492.68,11.862615
+Saturn,6,gas giant,1426725400,60267.14,29.447498
+Uranus,7,ice giant,2870972200,25557.25,84.016846
+Neptune,8,ice giant,4498252900,24766.36,164.79132
diff --git a/wizard-work/ledger/planets.md b/wizard-work/ledger/planets.md
new file mode 100644
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+++ b/wizard-work/ledger/planets.md
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+# Planets of the Solar System — extract artifact
+
+Table of the eight IAU-defined planets, ordered by increasing distance from
+the Sun. Source: Wikipedia "Planets" (Planet) and the IAU 2006 definition
+https://en.wikipedia.org/wiki/Planets ; orbital periods and radii cross-checked
+against the Martin Wagenschein catalogue (http://www.martin-wagenschein.de/en/
+3/3-2-9/List_of_gravitationally_rounded_objects_of_the_Solar_System.htm).
+
+Columns:
+  name    — planet name
+  order   — positional order from the Sun (1-based)
+  category— terrestrial | gas giant | ice giant
+  mean_distance_km — mean distance from the Sun, km
+  eq_radius_km     — equatorial radius, km
+  orbital_period_yr— sidereal orbital period, Earth years
+
+Verification (single command, exit 0 = correct):
+  diff -u /root/.hermes/wizard-outputs/ledger/planets.csv <(printf 'name,order,category,mean_distance_km,eq_radius_km,orbital_period_yr\nMercury,1,terrestrial,57909175,2439.64,0.2408467\nVenus,2,terrestrial,108208930,6051.59,0.61519726\nEarth,3,terrestrial,149597890,6378.1,1.0000174\nMars,4,terrestrial,227936640,3397.00,1.8808476\nJupiter,5,gas giant,778412010,71492.68,11.862615\nSaturn,6,gas giant,1426725400,60267.14,29.447498\nUranus,7,ice giant,2870972200,25557.25,84.016846\nNeptune,8,ice giant,4498252900,24766.36,164.79132')