@elite-dangerous-almanac/core / astro / rocheLimitsForDensity

rocheLimitsForDensity(primary, satelliteDensityKgM3): RocheLimits | null

Defined in: src/astro/body-physics.ts:175

Roche limits around a primary for a satellite of a stated density.

BodyProperties

The body being orbited. Needs a mass and a Radius.

number

The orbiting material's density in kg/m³.

RocheLimits | null

Both limits in metres from the primary's centre, or null when the primary's own density cannot be computed.

Use this when the satellite's density is assumed rather than measured — ring material, for instance, whose density comes from its class rather than from a mass and a radius (ringRocheLimits in ./body-rings is this function with that density filled in). When the satellite is a scanned body with a mass and a radius of its own, prefer rocheLimits, which reads the density off it.

If primary is not an object.

If satelliteDensityKgM3 is not a finite positive number — an assumed density is the caller's own figure, so a bad one is a mistake rather than a missing scan field.

import { rocheLimitsForDensity } from '@elite-dangerous-almanac/core/astro/body-physics';

// Icy particles (1000 kg/m³) around an Earth-density primary.
const limits = rocheLimitsForDensity({ MassEM: 1, Radius: 6_371_000 }, 1000);
limits?.rigid; // -> 14181242.2…
limits?.fluid; // -> 27642167.3…