A single-body meteoroid falls through an exponential atmosphere ρ(h) = ρ₀·e−h/H along a straight-line path at the entry angle. Drag decelerates it and heating ablates (evaporates) its mass; both depend on the same dynamic pressure term:
dv/dt = −(Cd·ρ(h)·A·v²)/m + g·sinθ
dm/dt = −(Ch·ρ(h)·A·v³)/(2Q)
dh/dt = −v·sinθ dx/dt = v·cosθ
A = πr², r = (3m / 4πδ)^(1/3)
ρ₀ = 1.225 kg/m³, scale height H = 7.16 km, drag coefficient Cd = 1.0, ablation efficiency Ch = 0.1, and Q is the material's heat of ablation — icy bodies ablate fastest, iron survives longest. The light curve plots the rate of kinetic-energy loss (drag heating + mass-loss), a proxy for the visual brightness astronomers record for real fireballs.
- Burn-up — mass drops below 0.1% of the original before reaching the ground.
- Impact — a meteorite (surviving mass) reaches h = 0.