Stellar Evolution Calculator

Explore the life cycle of stars based on mass, from protostar to stellar remnant

Stellar Parameters

Enter the initial mass of the star to calculate its evolution

M☉
Enter mass between 0.1 and 100 solar masses
Z/Z☉
Solar metallicity is 0.02
Main Sequence Lifetime
0.00
Billion years
Current Luminosity
0.00
Solar luminosities
Current Radius
0.00
Solar radii
Surface Temperature
0.00
Kelvin
★
Predicted Final State
Main Sequence Star
Stars like our Sun become white dwarfs
Stellar Evolution Timeline
Protostar
Main Sequence
Giant
Remnant
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0%
25%
50%
75%
100%

Understanding Stellar Evolution

Stellar evolution is the process by which a star changes over the course of its lifetime. Depending on its mass and metallicity, a star will go through various stages from formation to its end state.

Key Concepts:

  • Main Sequence: The longest stage where hydrogen fusion occurs
  • Mass-Lifetime Relation: t ∝ M⁻².5 (More massive stars have shorter lives)
  • Hertzsprung-Russell Diagram: Plots stars by temperature and luminosity
  • Stellar Remnants: White dwarfs, neutron stars, or black holes
Stellar Remnant Details

Based on the star's mass, it will end its life as a white dwarf, neutron star, or black hole.

Stars like our Sun (1 solar mass) become white dwarfs, while more massive stars collapse into neutron stars or black holes.

Stellar Evolution Principles

Stellar evolution describes the life cycle of stars based on their initial mass:

  • Protostar Stage: Gravitational collapse of a molecular cloud forms a protostar
  • Main Sequence: Hydrogen fusion in the core (longest stage of a star's life)
  • Giant Phase: After hydrogen exhaustion, star expands into red giant/supergiant
  • Remnant Stage: Final state as white dwarf, neutron star, or black hole
  • Mass-Luminosity Relation: L ∝ M3.5 for main sequence stars
  • Mass-Lifetime Relation: t ∝ M-2.5 for main sequence duration
Stellar Physics Formulas
L = L☉ × (M/M☉)3.5
tMS = 1010 × (M/M☉)-2.5 years
R = R☉ × (M/M☉)0.8
T = T☉ × (L/L☉)0.25 × (R/R☉)-0.5
Where:
L = Stellar luminosity
M = Stellar mass
tMS = Main sequence lifetime
R = Stellar radius
T = Surface temperature
☉ = Solar value reference

Star Classification

Type Mass (M☉) Lifetime Final State
O-type 15-90 10 million yrs Black Hole
B-type 2-15 100 million yrs Neutron Star
A-type 1.4-2 1 billion yrs White Dwarf
F-type 1.04-1.4 3 billion yrs White Dwarf
G-type (Sun) 0.8-1.04 10 billion yrs White Dwarf
K-type 0.45-0.8 30 billion yrs White Dwarf
M-type 0.08-0.45 100+ billion yrs White Dwarf

Stellar Remnants

Initial Mass Evolution Path Final State Characteristics
< 0.5 M☉ MS → Red Dwarf White Dwarf (He) Earth-sized, dim
0.5-8 M☉ MS → RG → PN White Dwarf (C/O) Earth-sized, hot core
8-25 M☉ MS → RSG → SN Neutron Star City-sized, dense
> 25 M☉ MS → RSG → SN Black Hole Event horizon, massive
MS = Main Sequence, RG = Red Giant, RSG = Red Supergiant, PN = Planetary Nebula, SN = Supernova

Metallicity (Z) significantly impacts stellar evolution:

  • Opacity: Higher metallicity increases opacity, reducing energy transport efficiency
  • Main Sequence Lifetime: Metal-rich stars have longer lifetimes due to reduced fusion rates
  • Stellar Winds: Metal-rich stars have stronger winds and higher mass loss rates
  • Convection: Metallicity affects convection zone depth and mixing
  • Final State: Metal-poor stars may form more massive remnants
  • Color and Luminosity: Metallicity affects stellar spectra and brightness

Population I stars (metal-rich) like our Sun have Z ≈ 0.0134, while Population II stars (metal-poor) have Z ≈ 0.001, and Population III stars (primordial) have Z ≈ 0.0001.

Mass is the most important factor in stellar evolution:

  • Low-mass stars (0.1-0.5 M☉): Live trillions of years, end as white dwarfs
  • Intermediate-mass stars (0.5-8 M☉): Live millions to billions of years, become red giants, end as white dwarfs
  • High-mass stars (8-20 M☉): Live millions of years, become supergiants, end in supernovae leaving neutron stars
  • Very high-mass stars (>20 M☉): Short lives (millions of years), become hypergiants, end in supernovae or hypernovae leaving black holes

Main sequence lifetime: t = 10¹⁰ * (M/M☉)⁻².5 years

As stars exhaust hydrogen in their cores, they expand into giant phases:

  • Subgiant Branch: Transition phase after main sequence
  • Red Giant Branch: Hydrogen shell burning, expansion to large size
  • Horizontal Branch: Helium core burning (for intermediate-mass stars)
  • Asymptotic Giant Branch (AGB): Double shell burning (hydrogen and helium)
  • Red Supergiant: Massive stars expand to enormous sizes (up to 1,000 solar radii)
  • Luminous Blue Variable (LBV): Unstable phase for very massive stars

Stellar death depends on mass and metallicity:

  • Low-mass stars: Shed outer layers to form planetary nebulae, leaving white dwarfs
  • Intermediate-mass stars: Similar to low-mass but with more energetic nebulae
  • High-mass stars: Core collapse supernovae (Type II), leaving neutron stars
  • Very high-mass stars: Hypernovae or pair-instability supernovae, leaving black holes

Metallicity effects:

  • Metal-poor stars: Produce more energetic supernovae and larger remnants
  • Metal-rich stars: Experience stronger mass loss, affecting remnant mass