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Type Alias: DistanceUnitType ​

ts
type DistanceUnitType =
  | 'm'
  | 'km'
  | 'au'
  | 'ly'
  | 'kly'
  | 'Mly'
  | 'Gly'
  | 'pc'
  | 'kpc'
  | 'Mpc'
  | 'Gpc';

Defined in: distance.ts:43

Canonical distance unit symbols for astronomy/space visualization.

Design principles ​

  • Canonical symbols only (no plurals / long names) for stable math & serialization.
  • Uses meters as the SI base; larger units have conventional scientific definitions.

Conventions ​

  • au - Astronomical Unit (IAU 2012 B2): 149 597 870 700 m (lowercase au is the IAU symbol).
  • ly family - Light-year based on the Julian year: 1 ly = c × 365.25 d = 9 460 730 472 580 800 m (with kly = 10³ ly, Mly = 10⁶ ly, Gly = 10⁹ ly).
  • pc family - Parsec defined from the arcsecond parallax: 1 pc = au × (648000 / π) ≈ 3.085677581×10¹⁶ m (kpc/Mpc/Gpc are ×10³/×10⁶/×10⁹).

Members ​

  • SI base & common multiple: m, km
  • Astronomical: au
  • Light-year family: ly, kly, Mly, Gly
  • Parsec family: pc, kpc, Mpc, Gpc

Example ​

ts
// Example shape often used alongside this type:
type Distance = { value: number; unit: DistanceUnitType };

const d1: Distance = { value: 1, unit: 'au' };
const d2: Distance = { value: 3.26, unit: 'ly' };
const d3: Distance = { value: 8, unit: 'kpc' };

See ​