const GALAXY_YOUNG_HEIGHT: Readonly<{ 6 fields }>
Natale et al. 2022 Table 1 and equations 2–4: stellar sech² heights. Applying their geometric young component to the measured arm ridges, and extending the flare beyond the Sun, are explicit model assumptions. https://doi.org/10.1093/mnras/stab2771
universe/src/galaxy/field.ts:55