All Tools

Star Lifecycle Visualizer

Three modes: an interactive HR diagram with 23 real stars, a stellar evolution pathway from nebula to end state, and a star properties calculator. Covers low-mass, medium-mass, and high-mass evolutionary tracks. Six presets from Red Dwarf to 50 M☉ Supergiant.

Mode

Presets

1.0 M☉
0.160 M☉

Hertzsprung-Russell Diagram

O-type (blue-white, hot)
G-type (yellow, sun-like)
K-type (orange)
M-type (red, cool)

Click any star to view its properties. Temperature increases to the left (astronomers' convention). Each major gridline represents a factor of 10 in luminosity.

Luminosity
1.00 L☉
Lifetime
10.0 Gyr
Radius
1.00 R☉
Spectral Type
G (5,778 K)

Reference Guide

HR Diagram

The Hertzsprung-Russell (HR) diagram plots stellar luminosity (vertical axis, logarithmic) against effective surface temperature (horizontal axis, reversed so hot stars are on the left). Developed independently by Ejnar Hertzsprung and Henry Norris Russell around 1910.

L∝R2T4L \propto R^2 T^4

Most stars fall on the diagonal main sequence, where they spend most of their lives fusing hydrogen. Giants and supergiants lie above and to the right; white dwarfs appear below and to the left.

O/B (blue-white)T > 10 000 K A/F (white-yellow)7 500 - 10 000 K G (yellow, Sun)~5 200 - 6 000 K K (orange)3 700 - 5 200 K M (red dwarf)T < 3 700 K

Stellar Evolution

All stars form in nebulae and pass through a protostar phase before reaching the main sequence. The end state depends almost entirely on the initial mass.

Mass rangePathEnd state
M < 0.08 M☉ Never ignites Brown dwarf
0.08 - 2 M☉ Red giant → PN White dwarf
2 - 8 M☉ Supergiant → SN Neutron star
M > 8 M☉ Supergiant → SN Black hole

Main Sequence Scaling

Stars on the main sequence obey tight power-law relationships between mass, luminosity, radius, and lifetime.

L∝M3.5tMS∝M−2.5L \propto M^{3.5} \qquad t_{MS} \propto M^{-2.5}

A 10 M☉ star is about 3 162 times more luminous than the Sun but lives only about 32 times shorter. A 0.3 M☉ red dwarf may outlive the current age of the universe.

RR⊙=L/L⊙ (T⊙T)2\frac{R}{R_\odot} = \sqrt{L/L_\odot}\,\left(\frac{T_\odot}{T}\right)^2

Stefan-Boltzmann relation connecting luminosity, radius, and effective temperature.

End States

The three compact remnants differ in density and escape velocity.

White Dwarf

Carbon-oxygen core ~Earth-sized, mass up to 1.4 M☉ (Chandrasekhar limit). Supported by electron degeneracy pressure.

Neutron Star

~20 km diameter, 1.4-3 M☉, supported by neutron degeneracy pressure. Pulsars are rapidly spinning neutron stars emitting radio beams.

Black Hole

Remnant mass exceeds ~3 M☉ (Tolman-Oppenheimer-Volkoff limit). Event horizon radius rₛ = 2GM/c² for a 10 M☉ black hole is ~30 km.