# ASTR 320 Reference Log

Tracks references, datasets, and visuals used in ASTR 320 materials, their verification status, and any human spot-check requirements. Provenance is labeled at one of three explicit levels throughout: **(1) live-verified this session** (fetched/extracted from a primary or authoritative source during this course's production), **(2) standard published/literature value not re-verified this session** (flagged for human spot-check), or **(3) synthetic/instructor-provided placeholder**. No purely synthetic (non-literature) numeric data is used anywhere in this package; every real-world number is either level 1 or level 2.

## Textbook

- OpenStax Astronomy 2e (openly licensed; local extracted copy `references/openstax-astronomy-2e-extracted.txt`; problem index `references/source-indexes/openstax-astronomy-2e-problem-index.md`). Chapter numbers cited in ASTR 320 materials use the **published edition's native chapter numbering**, following the ASTR 230/310 precedent for resolving the source index's internal −1 chapter-numbering offset. Status: chapter alignment inferred by extrapolation from adjacent verified ASTR 310 citations (Chapters 7, 9–13), not independently re-cross-checked against embedded figure/table numbering this session — flagged for human spot-check. Several ASTR 320 topics (the radiative-equilibrium disk-temperature/frost-line derivation, the moment-of-inertia interior-structure formalism, the hydrostatic scale-height and Jeans-escape derivations, the magnetopause pressure-balance derivation, and the Roche-limit and tidal-heating derivations) are **not covered at the introductory level in OpenStax Astronomy 2e at all** and are developed here from first principles instead; this is stated explicitly in `syllabus.html`, `schedule.html`, and each affected lecture's slides/notes rather than presented as an OpenStax-sourced result.

## Real Data Used in Lectures/Labs/Problem Sets

| Dataset | Used in | Source | Verification Level |
|---|---|---|---|
| TRAPPIST-1 system: star mass (0.0898 M⊙), radius (0.1192 R⊙), luminosity (5.66×10⁻⁴ L⊙), T_eff (2,566 K), distance (12.47 pc); seven planets b–h with semimajor axes (0.0115–0.0619 AU) and periods (1.51–18.77 d) | Lecture 14; Lab 07; PS 07 | Wikipedia "TRAPPIST-1" article, retrieved live this session (2026-09-24), citing Agol et al. (2021), *Planetary Science Journal* 2, 1; Ducrot et al. (2020), *A&A* 640, A112; Gillon et al. (2017), *Nature* 542, 456; Delrez et al. (2022), *A&A* 667, A59 | **Level 1: live-verified this session.** The only live-verified real-world dataset used in this course; the capstone unit's primary real system. |
| Eight solar-system planets: mass, radius, semimajor axis, orbital period, Bond albedo, observed mean/1-bar temperature | Lectures 01, 02, 07, 08, 09; Labs 01, 04, 06; PS 01, 04, 06 | JPL Planetary Fact Sheet / NASA Solar System Dynamics standard published values | **Level 2: not independently re-verified this session.** Human spot-check against the JPL Planetary Fact Sheet recommended. |
| Moon: mass, radius; Io, Europa, Enceladus: mass, radius, orbital semimajor axis, eccentricity; Jupiter/Saturn mass used as tidal primaries | Lectures 01, 09, 13; Labs 05, 07; PS 05, 07 | Standard published solar-system literature values (general astronomical knowledge, consistent with JPL Solar System Dynamics) | **Level 2: not independently re-verified this session.** Human spot-check recommended. |
| Ceres and Vesta: mass, radius, semimajor axis; interior differentiation/meteorite-family evidence | Lecture 02 (frost-line context); Lab 01; PS 01 | Dawn mission standard published values (Russell et al. 2012, 2016, *Science*) | **Level 2: not independently re-verified this session.** Human spot-check against Dawn mission publications recommended. |
| Moment of inertia factors: Earth (0.3307), Mars (0.3644), Moon (0.3931); Mercury (0.346, Margot et al. 2018 MESSENGER-derived) | Lecture 03; Lab 02; PS 02 | Standard published geophysical/geodetic values | **Level 2: not independently re-verified this session.** |
| Mars heat flow (≈22 mW/m², representative InSight-adjacent modeled estimate) and Earth heat flow (≈91.5 mW/m²); K-40, U-238, Th-232 radiogenic half-lives | Lecture 04; Lab 02; PS 02 | Standard published geophysical/nuclear-physics values (Mars heat flow explicitly noted as a representative modeled estimate given InSight's incomplete HP³ mole deployment, not a definitive direct measurement) | **Level 2: not independently re-verified this session.** |
| Lunar crater-density calibration values and chronology function; Apollo sample-return radiometric ages | Lecture 06; Lab 03; PS 03 | Standard published values consistent with the lunar chronology function (Neukum et al. 2001; Stöffler & Ryder 2001) and Apollo sample-return radiometric dating literature | **Level 2: not independently re-verified this session.** |
| Titan: mass, radius, surface temperature (≈93.7 K), Bond albedo | Lecture 13; Lab 04; PS 04 | Cassini-Huygens standard published values (Niemann et al. 2005, *Nature*; Fulchignoni et al. 2005, *Nature*) | **Level 2: not independently re-verified this session.** |
| Jupiter, Earth, Uranus, Neptune equatorial magnetic-field strengths (dipole moments/B0); solar-wind density and speed used for magnetopause standoff calculations | Lecture 10; Labs 05, 06; PS 05, 06 | Standard published values (Ness et al. 1986 for Uranus/Neptune; Connerney et al. 2018, *Geophysical Research Letters*, for Jupiter's Juno-derived field) | **Level 2: not independently re-verified this session.** |
| Uranus ring radii (including the epsilon ring) | Lecture 12; Lab 06; PS 06 | Standard published Voyager 2/stellar-occultation values (Elliot et al. 1977; Voyager Imaging Team 1986) | **Level 2: not independently re-verified this session.** |
| Saturn's A ring outer edge radius; ice density used in Roche-limit calculations | Lecture 12; Lab 06 | Standard published Cassini-era ring-system values | **Level 2: not independently re-verified this session.** |

## Synthetic Data

No purely synthetic (non-literature) numeric data is used in ASTR 320; every real-world dataset above is either live-verified this session (level 1, TRAPPIST-1) or a standard published literature value flagged for spot-check (level 2, all solar-system data). Physical constants (G, k, σ, AMU) are CODATA/standard values, not independently re-verified this session but not astronomically variable quantities requiring the same spot-check treatment as catalog data.

## Visuals

Lecture-specific SVG diagrams are generated programmatically per lecture (see `src/generate_astr320_content.py`) and are schematic/explanatory rather than photographic; no external image licensing is required.

## Corrections Made During Review

- **Escape-velocity comparative statement (Lecture 01):** the original draft hand-typed "4.25 km/s (Mercury) to 59.5 km/s (Jupiter)" in a bullet, which did not match this course's own computed Jupiter escape velocity (60.2 km/s, using the same `G_NEWTON`/mass/radius values as the deck's own worked-example table). Replaced the hardcoded string with a computed f-string drawing directly from the same `ESCAPE_VS` values used in the worked example, so the bullet and the table can never drift apart again.
- **Tidal-acceleration ranking (Lecture 13):** the original draft claimed "all three fractions are small (well under 1%)" and that "Io's fraction... is the largest of the three... correctly ranks Io as experiencing the strongest relative tidal stress." Independent recomputation showed Enceladus's tidal-acceleration fraction (1.25% of its own surface gravity) is actually larger than Io's (0.34%), because Enceladus's own surface gravity is so weak that even its smaller absolute tidal acceleration is a larger fraction of it. Corrected the text to state the true ranking, and to explicitly distinguish "largest fractional tidal stress relative to a moon's own weak gravity" (Enceladus) from "most tidally heated in absolute, geologically observable terms" (Io, still true and still the largest absolute tidal acceleration/heating power of the three) rather than conflating the two rankings.
- **Missing reading/scope note (Lecture 05):** unlike every other lecture, Lecture 05 (Plate Tectonics and Comparative Surface Geology) had no "Reading and Scope Note" section citing an OpenStax chapter/section, breaking the course's otherwise consistent per-lecture citation pattern. Added a reading note citing OpenStax Astronomy 2e Section 9.3–9.4, consistent with the section numbering already used for the adjacent Lectures 03, 04, and 06 (9.1, 9.1–9.2, and 9.5–9.6 respectively).

## Human Spot-Check Checklist Before Instructional Release

- [ ] Confirm TRAPPIST-1 system parameters against the primary Agol et al. (2021), Ducrot et al. (2020), and Delrez et al. (2022) papers directly (this session's fetch was from Wikipedia's synthesis of those sources, not the primary papers themselves).
- [ ] Confirm the eight solar-system planets' mass, radius, orbital, and albedo/temperature values against the current JPL Planetary Fact Sheet.
- [ ] Confirm Io, Europa, and Enceladus orbital/physical parameters and Jupiter/Saturn masses against JPL Solar System Dynamics.
- [ ] Confirm Ceres and Vesta parameters against Dawn mission publications (Russell et al. 2012, 2016).
- [ ] Confirm moment-of-inertia factors (Earth, Mars, Moon, Mercury) against current geodetic literature, including Margot et al. (2018) for Mercury.
- [ ] Confirm Mars and Earth heat-flow values against current InSight-era and terrestrial heat-flow literature.
- [ ] Confirm lunar crater-chronology calibration values against Neukum et al. (2001) and Stöffler & Ryder (2001).
- [ ] Confirm Titan's parameters against Cassini-Huygens publications (Niemann et al. 2005; Fulchignoni et al. 2005).
- [ ] Confirm Jupiter's, Earth's, Uranus's, and Neptune's magnetic-field values against Connerney et al. (2018) and Ness et al. (1986).
- [ ] Confirm Uranus's and Saturn's ring-system radii against Elliot et al. (1977), the Voyager Imaging Team (1986), and current Cassini-era ring literature.
- [ ] Verify exact OpenStax Astronomy 2e section/page numbers against the adopted print or PDF edition; this course's chapter/section citations were extrapolated by analogy from ASTR 310's verified citations rather than independently cross-checked against embedded figure/table numbering this session.