docs(ledgers): record source-backed findings on the figures of Iapetus and Ceres and the limbs of the Galilean and Uranian moons

docs/provenance/investigation-index.md

@@ -4,7 +4,7 @@ Generated by `node packages/bake/cli/report-investigations.mts --index --write`.
 decisions, not scientific readiness.
 
 **Ledgers:** 4394 of 5329 catalogued objects.
-**Open decisions:** 1427 (1187 unresolved, 240 deferred).
+**Open decisions:** 1429 (1187 unresolved, 242 deferred).
 
 ## Where the reopening evidence would appear
 
@@ -32,6 +32,7 @@ The source each decision examined. Watching these is how a decision reopens.
 | www.hou.usra.edu | 5 | ariel, hydra, nix, varuna, annefrank |
 | astro.troja.mff.cuni.cz | 4 | eurybates, orus, patroclus, polymele |
 | echo.jpl.nasa.gov | 4 | comet-209p, comet-2p, comet-8p, nereus |
+| naif.jpl.nasa.gov | 4 | annefrank, dinkinesh, ceres, iapetus |
 | almascience.eso.org | 3 | r-doradus, eps-eridani-disc, haumea |
 | archive.stsci.edu | 3 | neptune, m95-layers |
 | github.com | 3 | dinkinesh, wasp-43b, wasp-103b |
@@ -43,7 +44,6 @@ The source each decision examined. Watching these is how a decision reopens.
 | esahubble.org | 2 | abell-2744-layers, homunculus-nebula-layers |
 | esawebb.org | 2 | bullet-cluster-layers, cassiopeia-a-layers |
 | mast.stsci.edu | 2 | hd-189733b, wd-1856-534b |
-| naif.jpl.nasa.gov | 2 | annefrank, dinkinesh |
 | opus.pds-rings.seti.org | 2 | phoebe, metis |
 | pubs.usgs.gov | 2 | ganymede, mars |
 | science.nasa.gov | 2 | mercury, thebe |
@@ -159,6 +159,7 @@ The source each decision examined. Watching these is how a decision reopens.
 | `lorri-dataset` | 2 | hydra, nix | A meaningfully different view confirms the registration with interior holdouts and the mesh-to-kernel frame binding is verified. |
 | `mvic-leisa-composition` | 2 | hydra, nix | A target-specific composition product has interpretable calibration, coordinates and qualified transfer onto this source mesh. |
 | `north-south-degeneracy` | 2 | hd-189733b, wasp-43b | The orbit's sky orientation is measured. |
+| `oblate-figure` | 2 | ceres, iapetus | The shared sphere geometry places planetocentric latitudes on a spheroid and casts feature anchors onto it. |
 | `optical-scientific-surfaces` | 2 | sn263-beta, sn263-gamma | A component-specific observation, registered scientific map or qualified spin solution is located. |
 | `optical-surface-map` | 2 | comet-209p, comet-2p | Resolved surface observations and camera or terrain controls support a reproducible mapping. |
 | `other-hrii-scans` | 2 | comet-103p, comet-9p | A specific scan adds useful source facets with independently checked registration and valid nucleus spectra. |

src/objects/ariel/investigations.json

@@ -85,7 +85,7 @@
       "id": "limb-law",
       "subject": "Photometric law for the lighting overlays",
       "status": "unresolved",
-      "finding": "Helfenstein, Veverka and Thomas (1988) fitted Hapke models to Voyager whole-disc photometry of the five large Uranian moons. Only the abstract could be read (single-scattering albedo from 0.3 for Umbriel to 0.7 for Ariel, g near -0.3), and a whole-disc fit states no emission range. NASA's Reports of Planetary Geology and Geophysics Program for 1986 to 1989, which are open, print disc values for Miranda, Titania, Umbriel and Oberon, and none for Ariel. Schenk's 2020 mosaic history names ISIS photomet without its parameter file. Ariel keeps the shared sphere bank.",
+      "finding": "Helfenstein, Veverka and Thomas (1988) fitted Hapke models to Voyager whole-disc photometry of the five large Uranian moons. Only the abstract could be read (single-scattering albedo from 0.3 for Umbriel to 0.7 for Ariel, g near -0.3), and a whole-disc fit states no emission range. NASA's Reports of Planetary Geology and Geophysics Program for 1986 to 1989, which are open, print disc values for Miranda, Titania, Umbriel and Oberon, and none for Ariel. Schenk's 2020 mosaic history names ISIS photomet without its parameter file. Measured here on 2026-10-05, not a published law: on one calibrated clear frame at 20 degrees phase (FDS 26794.34, a 31 pixel disc) the lunar-Lambert weight that best fits the lit disc is 0.77, close to what Titania shows at that phase. Ariel keeps the shared sphere bank.",
       "evidence": [
         "https://doi.org/10.1016/0019-1035(88)90039-5",
         "https://ntrs.nasa.gov/citations/19880051927",

src/objects/callisto/investigations.json

@@ -46,15 +46,16 @@
       "id": "limb-law",
       "subject": "Photometric law for the lighting overlays",
       "status": "included",
-      "finding": "Lunar-like (Lommel-Seeliger) law of Squyres and Veverka (1981), which has no parameter. The Icarus paper is closed, but the authors' own summary in NASA's Reports of Planetary Geology Program 1980 (TM-82385, page 67) is open. It says Voyager clear-filter images at 10 to 124 degrees phase show that Ganymede's Cratered and Grooved Terrain and Callisto's Cratered Terrain are described closely by I = A F(alpha) mu0/(mu + mu0), and that bright craters follow it approximately. Flood-lit, this law is flat to the limb. F(alpha) is drawn in the report's Figure 1 and not printed, so frames with Shadows on carry no phase term. No emission range is printed; the limit 86.3 degrees is derived here from the outermost pixel of the finest clear-filter Voyager frame that holds the whole disc (Voyager 2 C2058321, 10.116 km per pixel) and is second class. Not used: USGS and the conference abstract on these mosaics (Becker et al. 2001) say they were normalized with a lunar-Lambert function with empirically derived values, which neither prints; Buratti (1991) fitted Hapke models to whole-hemisphere phase curves, which give no disc-resolved law. The Callisto photometry of Belgacem and colleagues covers regions only.",
+      "finding": "Lunar-like (Lommel-Seeliger) law of Squyres and Veverka (1981), which has no parameter. The Icarus paper is closed, but the authors' own summary in NASA's Reports of Planetary Geology Program 1980 (TM-82385, page 67) is open. It says Voyager clear-filter images at 10 to 124 degrees phase show that Ganymede's Cratered and Grooved Terrain and Callisto's Cratered Terrain are described closely by I = A F(alpha) mu0/(mu + mu0), and that bright craters follow it approximately. Flood-lit, this law is flat to the limb. F(alpha) is drawn in the report's Figure 1 and not printed, so frames with Shadows on carry no phase term. No emission range is printed; the limit 86.3 degrees is derived here from the outermost pixel of the finest clear-filter Voyager frame that holds the whole disc (Voyager 2 C2058321, 10.116 km per pixel) and is second class. Not used: USGS and the conference abstract on these mosaics (Becker et al. 2001) say they were normalized with a lunar-Lambert function with empirically derived values, which neither prints; Buratti (1991) fitted Hapke models to whole-hemisphere phase curves, which give no disc-resolved law. The Callisto photometry of Belgacem and colleagues covers regions only. McEwen and Soderblom (1983), an open summary in NASA TM-86246 (page 261), solved the limb darkening from pairs of Voyager images of the same ground: 16 pairs on Callisto and one on Ganymede, both consistent with lunar-like scattering. That is an independent disc-resolved result for the same law.",
       "evidence": [
         "https://ntrs.nasa.gov/citations/19810007392",
         "https://doi.org/10.1016/0019-1035(81)90203-7",
         "https://ntrs.nasa.gov/citations/19810058926",
         "https://opus.pds-rings.seti.org/opus/api/metadata/vg-iss-2-j-c2058321.json",
         "https://astrogeology.usgs.gov/search/map/callisto_voyager_galileo_image_mosaic_map",
         "https://www.lpi.usra.edu/meetings/lpsc2001/pdf/2009.pdf",
-        "https://ntrs.nasa.gov/citations/19910063813"
+        "https://ntrs.nasa.gov/citations/19910063813",
+        "https://ntrs.nasa.gov/citations/19840015363"
       ],
       "revisitWhen": "The paper's phase functions and emission range, or a newer global disc-resolved Callisto law, are read."
     },

src/objects/ceres/README.md

@@ -27,7 +27,7 @@ Source selections, recorded trials and open questions are in the [investigation
 
 ## Processing
 
-The mesh is a sphere of 469.7 km with no resolved shape model. The maps share a global equirectangular grid. Exactly black pixels connected to the southern border are marked with a neutral gray grid; no terrain is inferred. The Dawn FC2 mosaic is orthorectified in the body-fixed frame by its producers ([PDS record](https://pds.nasa.gov/ds-view/pds/viewProfile.jsp?dsid=DAWN-A-FC2-5-CERESMOSAIC-V1.0)); its registration does not depend on a crater match by cssEarth.
+The mesh is a sphere of 469.7 km with no resolved shape model. Ceres is flattened by 7.5% (482 km at the equator, 446 km at the poles, [dawn_ceres_v05.tpc](https://naif.jpl.nasa.gov/pub/naif/DAWN/kernels/pck/dawn_ceres_v05.tpc)); the [ledger](investigations.json) says what in the shared geometry must change before that can be drawn. The maps share a global equirectangular grid. Exactly black pixels connected to the southern border are marked with a neutral gray grid; no terrain is inferred. The Dawn FC2 mosaic is orthorectified in the body-fixed frame by its producers ([PDS record](https://pds.nasa.gov/ds-view/pds/viewProfile.jsp?dsid=DAWN-A-FC2-5-CERESMOSAIC-V1.0)); its registration does not depend on a crater match by cssEarth.
 
 The Ammonium band is the 3.1 µm band depth between the reflectance maxima in 2.91–3.01 µm and 3.19–3.24 µm. `packages/bake/authoring/dawn/vir-mosaic.mts` builds each line's camera from the Dawn SPICE kernels, converts radiance to I/F, removes stripes and spikes, brings each cube to 30° phase, sets aside cubes that disagree with all their neighbours, and blends seams as ISIS3's `noseam` does, at 16 pixels/degree (0.5 km). Survey and HAMO set every cell they saw; LAMO, Approach and set-aside cubes fill gaps. The map is 98.7% covered. The [phase fit and rejections](source/science/vir-reduction/photometry.json), [recipe](source/science/vir-reduction/recipe.json) and [receipt](source/science/vir-reduction/receipt.json) are recorded.
 

src/objects/ceres/investigations.json

@@ -345,6 +345,18 @@
         "https://doi.org/10.3847/1538-3881/ab8305"
       ],
       "revisitWhen": "A published resolved thermal-inertia or emissivity map of Ceres from these ALMA data, or a new ALMA epoch whose surface-fixed residuals repeat between independent epochs."
+    },
+    {
+      "id": "oblate-figure",
+      "subject": "Figure of the globe",
+      "status": "deferred",
+      "finding": "The globe is a 469.7 km mean-radius sphere, but Ceres is flattened: the Dawn project's NAIF kernel dawn_ceres_v05.tpc gives an average equatorial radius of 482 km and a polar radius of 446 km (equivalent sphere 470 km), so the poles sit 7.5% closer to the centre than the equator, about 17 pixels of the 460 pixel globe. Tried on 2026-10-05 and withdrawn: setting the recipe to that spheroid stops the bake, and the stop is right. Three things in the shared sphere lane hold only for a nearly round body such as Mars (0.6%). The feature step compares the Gazetteer's 470 km datum sphere with the authored radius, which becomes the 482 km equatorial radius, and refuses beyond 1%. It then places anchors on a sphere, so at 7.5% labels would float above the poles. And the mesh places a map latitude at the spheroid's parametric latitude, up to 2.2 degrees from the planetocentric latitude the maps use. Drawing the figure correctly means changing that shared geometry, which also moves Mars, Uranus and Neptune.",
+      "evidence": [
+        "https://naif.jpl.nasa.gov/pub/naif/DAWN/kernels/pck/dawn_ceres_v05.tpc",
+        "https://github.com/layoutit/css.earth/blob/main/packages/bake/src/surface-geometry/surface.ts",
+        "https://github.com/layoutit/css.earth/blob/main/packages/bake/src/objects/surface-features/surface-features.ts"
+      ],
+      "revisitWhen": "The shared sphere geometry places planetocentric latitudes on a spheroid and casts feature anchors onto it."
     }
   ]
 }

src/objects/europa/README.md

@@ -82,7 +82,7 @@ The withheld composition grids match the original release exactly after float32
 - **Monochrome inserts:** Smaller brightness steps remain where one gain per image cannot follow the phase-angle change in albedo, and shadows keep their original direction. Photographs beyond 85° incidence are not shown. Relative control uncertainties are about 247 m in latitude and 307 m in longitude; the older global mosaic has different registration errors. The delivered grid is about 1.20 km at the equator, so finer native detail is not shown. Atlas seams can show at extreme close zoom.
 - **False color:** 756 nm, 559 nm and 404 nm are shown as red, green and blue. This is not natural color. About 14.3% of the sphere has usable three-band coverage.
 - **Illumination:** The disk correction is approximate: no phase-angle normalization, fitted scattering model, or removal of cast shadows.
-- **Lighting law:** One law lights every terrain; the paper's chaos and crater rows differ from the ridged-plains row used. Its emission limit, 84.5°, is derived here, not stated by the paper. The fits cover 10° to 128° phase, so the flood-lit default view (0°) and frames beyond 128° use the printed lines outside that range. The line for f crosses zero at 111°; from there the lit side follows the Lambert term alone. The paper's own fit of its 10° image (A = 0.69, f = 1.17, its Figure 6) gives a darker flood-lit limb, 0.61 of the centre, than the lines of Table 2.
+- **Lighting law:** One law lights every terrain; the paper's chaos and crater rows differ from the ridged-plains row used. Its emission limit, 84.5°, is derived here, not stated by the paper. The fits cover 10° to 128° phase, so the flood-lit default view (0°) and frames beyond 128° use the printed lines outside that range. The line for f crosses zero at 111°; from there the lit side follows the Lambert term alone. The paper's own fit of its 10° image (A = 0.69, f = 1.17, its Figure 6) gives a darker flood-lit limb, 0.61 of the centre, than the lines of Table 2. McEwen and Soderblom (1983) found the same from 44 image pairs at 3° to 30° phase (0.64 at 3°), so the default view's limb is probably drawn too bright; the [ledger](investigations.json) says why it is not changed yet.
 - **Infrared:** This is a spectral color display, not an abundance map. Its 2010 registration grid is not the 2021 control grid.
 - **Feature outlines:** Craters and faculae trace a rim circle and other types their extent box; these are not published nomenclature boundaries.
 - **Composition reuse:** The Zenodo record is `other-open`, but gives no explicit terms for reusing the numerical release. The three composition views are withheld until such terms exist. SPHERE diffraction limits resolved features to about 150 km.

src/objects/europa/investigations.json

@@ -112,13 +112,15 @@
       "id": "limb-law",
       "subject": "Photometric law for the lighting overlays",
       "status": "included",
-      "finding": "Lommel-Seeliger plus Lambert law of Dhingra, Buratti and Seignovert (2021), fitted to 21 resolved Voyager 2, Galileo and New Horizons clear-filter images: I/F = A f mu0/(mu0 + mu) + (1 - A) mu0, with the ridged-plains lines of its Table 2, A = 0.871 - 0.003 alpha and f = 1.556 - 0.014 alpha (alpha in degrees), fitted at 10 to 128 degrees phase, relative to the flood-lit disc centre. A lighting overlay has one law for the whole body: the ridged-plains row is used because the paper says that unit covers more than half of Europa and that the parameters differ little between terrains. No map pixel changes. The paper states no emission range; the limit 84.5 degrees is derived here from the outermost pixel of the finest full-disc image in its Table 1 (Voyager 2 wide-angle C2065221, 14.465 km per pixel) and is second class. The same table's Minnaert lines are not used: Minnaert grows without bound toward the limb while its exponent is below 1. Buratti and Veverka (1983) introduced this form for Europa; its values could not be read. Belgacem et al. (2020) give Hapke fits for 20 regions only.",
+      "finding": "Lommel-Seeliger plus Lambert law of Dhingra, Buratti and Seignovert (2021), fitted to 21 resolved Voyager 2, Galileo and New Horizons clear-filter images: I/F = A f mu0/(mu0 + mu) + (1 - A) mu0, with the ridged-plains lines of its Table 2, A = 0.871 - 0.003 alpha and f = 1.556 - 0.014 alpha (alpha in degrees), fitted at 10 to 128 degrees phase, relative to the flood-lit disc centre. A lighting overlay has one law for the whole body: the ridged-plains row is used because the paper says that unit covers more than half of Europa and that the parameters differ little between terrains. No map pixel changes. The paper states no emission range; the limit 84.5 degrees is derived here from the outermost pixel of the finest full-disc image in its Table 1 (Voyager 2 wide-angle C2065221, 14.465 km per pixel) and is second class. The same table's Minnaert lines are not used: Minnaert grows without bound toward the limb while its exponent is below 1. Buratti and Veverka (1983) introduced this form for Europa; its values could not be read. Belgacem et al. (2020) give Hapke fits for 20 regions only. McEwen and Soderblom (1983), an open summary in NASA TM-86246 (page 261), solved the limb darkening from pairs of Voyager images of the same ground, 44 pairs on Europa: its scattering is uniform across materials and wavelength, with a Minnaert exponent K = 0.64 - 0.005a + 0.00066a^2 - 0.000012a^3 from 3 to 30 degrees phase. At 3 degrees that is 0.63, a flood-lit limb of 0.64 of the centre at 0.98 of the radius, where the Table 2 lines used here give 0.86 when carried below their 10 degrees, and the paper's own 10 degree image gives 0.61. That image's Minnaert fit is k = 0.65 for the whole disc and 0.64 for ridged plains (its Figures 4 and 6), the value the 1983 polynomial gives at 10 degrees (0.644); the paper's Table 2 line for k, 0.532 + 0.004a, gives 0.57 there. Two independent low-phase results therefore say the default view's limb is drawn too bright, and both of the paper's straight lines, fitted across 10 to 128 degrees, miss its own lowest-phase image. Not changed: the 1983 law stops at 30 degrees, so it cannot light every frame with Shadows on, and the two results cannot be joined into one published law.",
       "evidence": [
         "https://doi.org/10.3847/PSJ/ac06d6",
         "https://hal.science/hal-04259112",
         "https://opus.pds-rings.seti.org/opus/api/metadata/vg-iss-2-j-c2065221.json",
         "https://ntrs.nasa.gov/citations/19830059564",
-        "https://doi.org/10.1016/j.icarus.2019.113525"
+        "https://doi.org/10.1016/j.icarus.2019.113525",
+        "https://ntrs.nasa.gov/citations/19840015363",
+        "https://doi.org/10.48577/jpl.6IR6VA"
       ]
     },
     {