Star Swap

Swap the central star and watch real Kepler's-law physics change every planet's orbital speed instantly. Planets that fall inside the Roche limit get torn apart.

Sun-like Star

Mass: 1 M☉

Radius: 696000 km · Density: 1408 kg/m³

All planets orbiting safely

A normal main-sequence star fusing hydrogen into helium in its core. Our own Sun. Planets orbit stably at their real-world distances since density and gravity are balanced as expected.