⊕ Astrophyzix Asteroid Impact Simulator V3.0
RK4 atmospheric entry · Holsapple–Schmidt π-scaling · Collins / Pierazzo / Ward–Asphaug modules
Live
T+0.000s
FRM0
PHZIDLE
ALT—
VEL—
MODESURFACE
Impact detected
Impact Parameters
Asteroid Diameter
500 m
Entry Velocity
20 km/s
Impact Angle
45°
Impactor Density
2500 kg/m³
Observer Distance
100 km
Composition
Ocean Depth (if water)
Target World
Earth
Moon
Mars
Venus
Mercury
Jupiter
Titan
Ceres
Surface Type
Quick Presets
Chelyabinsk 2013
19 m · Stony · 19 km/s
Tunguska 1908
60 m · Carbon · 27 km/s
Barringer
50 m · Iron · 12.8 km/s
99942 Apophis
370 m · Stony · 12.6 km/s
101955 Bennu
500 m · Carbon · 12.7 km/s
Chicxulub K-Pg
10 km · Stony · 20 km/s
Impact Analysis
Event Classification
— Awaiting —
Set parameters, then simulate.
Impactor Properties
Diameter—
Mass—
Entry Velocity—
Kinetic Energy—
TNT Equivalent—
Earth Recurrence—
Atmospheric Entry (RK4)
Outcome—
Breakup Alt.—
Airburst Alt.—
Impact Velocity—
Surviving Mass—
Atm. Energy Loss—
Energy Deposition vs Altitude
dE/dz · pancake / drag integrator
Crater Dimensions
Transient Diam.—
Final Diameter—
Depth—
Ejecta Blanket—
Crater Type—
Formation Time—
Melt · Vapor · Ejecta
Melt Volume—
Melt / Impactor—
Vapor Fraction—
Peak Shock—
Ejecta Velocity—
Escape Ejecta?—
Environmental Effects
Seismic (Mw)—
Fireball Radius—
Thermal @ observer—
Blast @ observer—
Overpressure—
Optical Yield—
Tsunami & Climate
Cavity Diam.—
Wave @ observer—
Wave @ 1000 km—
Run-up class—
Global dust—
Climate tier—
Global Severity (log energy)
0%
Crater Size Index
0%
Module Identity
Module IDAIS-WIDE-v3.0.0 © 2026 Astrophyzix Observatory
Hosthttps://www.astrophyzix.com
EngineHTML5 Canvas · Vanilla JS ES2020 · RK4 entry integrator
V3.0 Build Date2026-09-20
Status● Active
LayoutWide module · max-width 700 px
v3.0 Scientific Upgrades
Entry integratorReplaced the analytic Chyba altitude estimate with a 4th-order Runge–Kutta integration of drag, gravity, ablation and pancake spreading (Chyba et al. 1993; Collins et al. 2005).
Energy depositiondE/dz profile stored along the trajectory. Airburst altitude is the height of peak energy deposition, not a point-source guess.
Crater gravity termNormal velocity v sin θ used in π₂. Planet-specific simple–complex transition diameters replace the single 3.8/g Earth fit.
Melt / vaporPierazzo et al. (1997) energy-scaling melt volume with Pierazzo & Melosh (2000) obliquity correction. Vapor fraction from melt number.
SeismicCollins et al. (2005) moment-magnitude estimator M = 0.67 log₁₀(E) − 5.87, E in joules of surface-coupled kinetic energy.
Observer fieldBlast overpressure and thermal exposure evaluated at a user distance via cube-root yield scaling (Collins 2005).
TsunamiWard & Asphaug (2000, 2002) cavity-to-wave attenuation with ocean-depth cap and geometric + dispersive decay.
Climate tierToon et al. (1997) dust / soot / firestorm energy thresholds, applied only as order-of-magnitude class labels.
RecurrenceBrown et al. (2002) Earth bolide flux N(>E) = 3.7 E−0.90 yr⁻¹ (E in kt). Extrapolated above the calibrated 0.1–20 kt window and flagged as such.
WorldsAdded Titan (N₂ atmosphere, icy crust) and Ceres (airless, low-g). Jupiter treated at the 1-bar reference surface.
Atmospheric Entry Integrator
ρ(z) = ρ₀ exp(−z / H)
dv/dt = g sinθ − (C_D ρ A v²) / (2 m)
dz/dt = −v sinθ
dm/dt = − (C_H ρ A v³) / (2 Q) (ablation)
breakup when ρ v² ≥ Y
d²r/dt² = (C_D ρ v²) / (2 ρᵢ r) (pancake, post-breakup)
dv/dt = g sinθ − (C_D ρ A v²) / (2 m)
dz/dt = −v sinθ
dm/dt = − (C_H ρ A v³) / (2 Q) (ablation)
breakup when ρ v² ≥ Y
d²r/dt² = (C_D ρ v²) / (2 ρᵢ r) (pancake, post-breakup)
C_D1.7 (blunt body; Chyba 1993 uses ~1–2)
C_H0.10 heat-transfer coefficient
QHeat of ablation: stone 8 MJ kg⁻¹, carbon 5, iron 8, comet 2.5 (Chyba table)
Airburst def.Altitude of max dE/dz after pancake radius exceeds 2 r₀, or residual mass < 1% before ground.
SchemeClassical RK4, Δt = 0.02 s, ceiling 0.8 × planet radius of curvature ignored (flat-atmosphere).
Gravity bending of the trajectory and lift are omitted. Multi-body fragmentation after pancake decoupling is not resolved; residual mass is treated as a single equivalent body.
Physics Model Provenance
Crater ScalingHolsapple, K.A. (1993). Ann. Rev. Earth Planet. Sci. 21, 333–373. Combined strength/gravity π-group; ν = 0.4.
π groupsπ₂ = 3.22 g a / (v_n²) × (ρ_t/ρ_i)^{1/3}; π₃ = Y / (ρ_t v_n²). Transient diameter from min(gravity, strength) branch.
Complex cratersMelosh, H.J. (1989). Impact Cratering. D_final = 1.17 D_tc^{1.13} / D_sc^{0.13} above the planet-specific simple–complex transition.
D_sc (km)Earth 3.2 (sed) / 4.0 (xtal); Moon 18.8; Mars 8; Mercury 11; Venus 4; Titan 8; Ceres ~90 (g-scaled). Pike / Melosh / Krüger et al. 2018.
Peak-ring / basinPeak-ring onset ≈ 5 × D_sc; multi-ring ≈ 20 × D_sc (morphologic, not dynamic).
Formation timet_form ≈ 0.8 √(D_tc / (2 g)) (Schmidt–Housen / Melosh excavation timescale).
Environmental FXCollins, Melosh & Marcus (2005). Earth Impact Effects Program. Meteoritics 40(6), 817–840.
FireballR_f ≈ 0.002 E^{1/3} (E in J, R in m) — yield scaling, Collins eq. 32.
Airburst modelChyba, Thomas & Zahnle (1993). Nature 361, 40–44. Pancake ODE as implemented in Collins 2005 / 2017.
MeltPierazzo, Vickery & Melosh (1997). Icarus 127, 408–423. V_m / V_i = 10^a (v_n² / E_m)^μ, a ≈ −0.80, μ ≈ 0.67, E_m (granite) = 5.2 MJ kg⁻¹.
Oblique meltPierazzo & Melosh (2000). Icarus 145, 252–261. Melt retained ≈ 1.0 (≥45°), 0.5 (30°), 0.1 (15°) relative to vertical.
TsunamiWard & Asphaug (2000) Icarus; (2002) DSR-II. A(r) = min(D_c, h) / (1 + r / R_c)^w with w ≈ 0.5 + 0.575 exp(−0.035 R_c / h).
Climate / dustToon et al. (1997). Rev. Geophys. 35(1), 41–78.
FluxBrown et al. (2002). Nature 420, 294–296. log₁₀ N = 0.5677 − 0.90 log₁₀ E_kt.
⚠ Results are order-of-magnitude estimates for education and science communication. Not for hazard assessment, insurance, or civil-defence planning. Crater diameters ±50%; energy-coupled effects ±1 order of magnitude.
Planetary Data Sources
PrimaryNASA Planetary Fact Sheets (Williams, D.R., NSSDCA)
AtmosphereEarth: US Standard / MSIS ρ₀=1.225 kg m⁻³, H=8.5 km. Mars Climate Database-class ρ₀=0.020, H=11 km. Venus VIRA ρ₀=65, H=16 km. Titan N₂ ρ₀=5.4, H=40 km. Jupiter 1-bar ρ₀=0.16, H=27 km.
Last Verified2026-09
Known Limitations
Oblique cratersElliptical planform (Elbeshausen / Collins) is not drawn. Angle enters via v_n = v sinθ in π₂ and melt correction only.
FragmentationSingle-body pancake. No strewn-field, no Hills–Goda debris cloud, no Avramenko chain reaction.
TsunamiFlat-bottom ocean of constant depth; no coastline bathymetry, no edge waves, no landslide secondary source.
Very large eventsπ-group scaling is an extrapolation above ~500 km crater diameter and for planetary-scale (magma ocean) events.
Jupiter / TitanGas-giant “craters” are transient atmospheric cavities; icy-crust melt uses the same E_m as water ice.
FluxBrown 2002 calibrated 0.1–20 kt. Recurrence at Chicxulub energies is an unchecked power-law extrapolation.
Governance & Usage Policy
Intended UseEducation, science communication, scenario visualisation on astrophyzix.com.
ProhibitedOperational hazard assessment · insurance claims · civil defence planning.
Accuracy TierIndicative — ±50% on crater dimensions, ±1 OOM on energy effects.
Changelog
v3.0.0700 px wide rebuild. RK4 drag/ablation/pancake integrator with dE/dz profile. Pierazzo melt + obliquity. Collins Mw. Ward–Asphaug tsunami with ocean depth. Observer-distance blast/thermal. Brown 2002 recurrence. Toon climate tier. Titan + Ceres. Chelyabinsk + Barringer presets. Provenance rewrite.
v2.1.0Narrow layout rebuild. Provenance drawer. Professional UI refresh.
v2.0.0Airburst model (Chyba 1993). Tsunami module (Weiss & Wünnemann 2008).
v1.0.0Initial release. Pi-group crater scaling, six planet targets, canvas particle system.