astro.Function.absoluteBolometricMagnitude

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

Function: absoluteBolometricMagnitude()

absoluteBolometricMagnitude(body): number | null

Defined in: src/astro/star-physics.ts:200

A star's absolute bolometric magnitude, worked out from how big and how hot it is.

Parameters

body

BodyProperties

The star. Needs Radius in metres and SurfaceTemperature in kelvin.

Returns

number | null

The absolute bolometric magnitude — smaller is brighter, and a luminous star is negative — or null when either field is missing.

Remarks

Stefan–Boltzmann gives the luminosity — L/L☉ = (R/R☉)² · (T/T☉)⁴ — and the magnitude follows as M☉ − 2.5 log₁₀(L/L☉).

The reason to compute one when the scan usually reports AbsoluteMagnitude directly is that some stars carry no magnitude at all: a white dwarf is written with a radius and a temperature and nothing else to place it by. The two figures are not interchangeable — this is bolometric, over all wavelengths, while a reported magnitude is closer to visual — so expect them to differ by a magnitude or so on a very hot or very cool star, and use this as the fallback rather than the correction.

Throws

If body is not an object.

Example

import { absoluteBolometricMagnitude } from '@elite-dangerous-almanac/core/astro/star-physics';

// A star the size and temperature of the Sun is the Sun's magnitude.
absoluteBolometricMagnitude({ Radius: 695_700_000, SurfaceTemperature: 5772 }); // -> 4.74

// An Earth-sized white dwarf at 15 000 K: faint despite being fiercely hot.
absoluteBolometricMagnitude({ Radius: 6_371_000, SurfaceTemperature: 15_000 }); // -> 10.78…