ZAMS classification
Sol
Main Sequence · reached 40.012471 Myr after formation
[Fe/H] 0

Star Simulation
Input the mass and metallicity of a star, and this simulation will simulate the progression of stellar life. This is based on science* instead of CLT, surnames, and birth dates.
ZAMS classification
Main Sequence · reached 40.012471 Myr after formation
[Fe/H] 0[Fe/H] 0 defines the starting composition model.
Radius scale 1× is applied to the mass-calibrated ZAMS base.
RGB → He ignition / clump / AGB reaches Main Sequence after 40.012471 Myr.
0.853793 R☉ · 1 M☉ · 0.625464 L☉.
Realistic-scale time traveller
The Universe clock is paused.
Live stellar distribution
View the positions of your stars on this graph.
Matching stars will appear here for one-click highlighting.
Search above, select a leaderboard star, or select its point in the diagram.
Both axes are logarithmic. Select a point to highlight its birth-to-delisting trajectory; select it again to clear. Hold a point for one second to open its full specifications. Hover or focus for its name, SpectralC, Teff, and luminosity. Protostars and pre-main-sequence stars fade in as they form. Every Universe star follows one natural lifecycle: its final fade uses the physical-age interval corresponding to the reference track’s last 116.9–117 checkpoints, then the point, hover tag, and highlighted path delist together. Universe uses no alternate death-type selector. Values beyond 100–200,000 K or 10−6–107 L☉ are pinned to the nearest edge.
Live simulation registry
Universe stars follow the shared realistic-scale clock and are ranked by the selected physical property.
Enter a display name and stellar mass above. The first simulation entry will begin at t+0 years.
Important model limitation
Universe mode is an educational approximation based on representative, approximately solar-metallicity single-star tracks. A star’s real evolution depends on composition, rotation, mass loss, magnetic activity, multiplicity, and the exact stellar model.
The [Fe/H] temperature curve is a smooth game approximation informed by MIST/PARSEC. Finite-metallicity ZAMS radii use the Tout et al. (1996) fit; extreme metallicity bins are clamped to its calibrated range. Population III temperatures and massive-star radii use the workbook’s separate Schaerer-based model. Stage timing follows the physical-age track and is not recalibrated by metallicity.
Mass-to-spectrum mapping, stage timing, late-stage outcomes, temperature, radius, mass, luminosity, and hydrogen values may differ substantially from a matched stellar-model analysis. Displayed precision is computational precision, not physical certainty. Do not use these values for research, engineering, navigation, or safety-critical decisions.