Every star here obeys two real main-sequence scaling laws relating mass to how it lives and dies:
L / Lโ = (M / Mโ)^3.5
t_MS = 10^10 ร (M / Mโ)^-2.5 years
R / Rโ โ (M / Mโ)^0.8
T_eff = 5778K ร (L / Rยฒ)^0.25
Luminosity rises with roughly the 3.5th power of mass, but the fuel supply only grows linearly with mass โ so lifetime falls off as mass^-2.5. A 20 Mโ blue star is ~2.4 million times more luminous than the Sun but burns through its core hydrogen in only a few million years. A 0.3 Mโ red dwarf is dim but will still be fusing hydrogen long after the Sun is gone.
- Mass slider + Launch โ adds a new star to the race at the chosen mass (0.1โ40 Mโ).
- Time speed โ how many simulated years pass per real second; higher speeds let low-mass stars' multi-billion-year lifetimes finish in view.
- When a star exhausts its core hydrogen it swells into a red giant, then collapses to its end state: a white dwarf (M < 8 Mโ), a neutron star (8โ25 Mโ), or a black hole (M > 25 Mโ), following the Chandrasekhar / neutron-degeneracy mass limits.