astro.Function.mainSequenceLifetime

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

Function: mainSequenceLifetime()

mainSequenceLifetime(body): number | null

Defined in: src/astro/star-physics.ts:162

How long a star of a given mass spends on the main sequence, in millions of years.

Parameters

body

BodyProperties

The star. Needs StellarMass.

Returns

number | null

The lifetime in millions of years, or null when no usable stellar mass is written — which is the case for every planet, and for a scan that resolved nothing.

Remarks

The standard scaling t ≈ 10 Gyr · (M/M☉)^−2.5, anchored so that the Sun reads 10 Gyr. Mass is what sets a star's whole life: doubling it cuts the lifetime more than fivefold, because the star burns its larger fuel supply very much faster.

Compare it against Age_MY to judge a generated star. An ordinary star older than its own main-sequence lifetime should already have left it, and a giant younger than one should not yet have arrived.

Throws

If body is not an object.

Example

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

mainSequenceLifetime({ StellarMass: 1 }); // -> 10000

// A heavy blue star lives a few million years.
mainSequenceLifetime({ StellarMass: 20 }); // -> 5.5…

// A red dwarf outlives the universe many times over.
mainSequenceLifetime({ StellarMass: 0.2 }); // -> 559016.9…

mainSequenceLifetime({ MassEM: 1 }); // -> null