Class StarSystem

constructor

• new StarSystem(input?: SystemInput): StarSystem

  Builds a system; anything not given uses DEFAULT_SYSTEM.

  Parameters

  • input: SystemInput = {}

  Returns StarSystem

Readonlybodies

Readonlyoptions

home

• get home(): Body

  The home planet.

  Returns Body

moon

• get moon(): Body | undefined

  The home planet's moon, if any.

  Returns Body | undefined

star

• get star(): Body

  The central star.

  Returns Body

apsides

• apsides(
      body: string | number,
      from?: number,
  ): Apsides & { names: [string, string] } | null

  Periapsis/apoapsis of a body's orbit around its parent, with their conventional names (perigee/apogee for the home planet's moons, perihelion/aphelion around the star). null for the star.

  Parameters

  • body: string | number
  • from: number = 0

  Returns Apsides & { names: [string, string] } | null

get

• get(body: string | number): Body

  Looks up a body by name or index.

  Parameters

  • body: string | number

  Returns Body

  Throws

  If there is no such body.

localState

• localState(body: string | number, time: number, out?: OrbitState): OrbitState

  Position relative to the parent at time (seconds since J2000), metres.

  Parameters

  • body: string | number
  • time: number
  • Optionalout: OrbitState

  Returns OrbitState

orientation

• orientation(body: string | number, time: number): Mat3

  Orientation at time: the rotation taking body-fixed vectors into the star frame (tilt, then spin). The tilt leans the north pole towards ecliptic longitude 90° (−Z), like Earth's.

  Parameters

  • body: string | number
  • time: number

  Returns Mat3

period

• period(body: string | number): number

  Orbital period of a body around its parent, seconds (0 for the star).

  Parameters

  • body: string | number

  Returns number

position

• position(body: string | number, time: number, out?: Vec3): Vec3

  Position in the star frame at time, metres.

  Parameters

  • body: string | number
  • time: number
  • out: Vec3 = ...

  Returns Vec3

solarDay

• solarDay(body?: string | number): number

  Length of a body's solar day (noon to noon), seconds. For moons, relative to their parent's star.

  Parameters

  • body: string | number = 1

  Returns number

spin

• spin(body: string | number, time: number): number

  Spin angle (radians) about the body's own +Y axis at time.

  Parameters

  • body: string | number
  • time: number

  Returns number

velocity

• velocity(body: string | number, time: number, out?: Vec3): Vec3

  Velocity in the star frame at time, m/s.

  Parameters

  • body: string | number
  • time: number
  • out: Vec3 = ...

  Returns Vec3