Astronomy
Two stars, one centre of mass
Change the mass ratio. Both stars orbit their common centre of mass; compare their speeds and see the brighter star’s reflex motion.
The model and its limits
Circular two-body orbit; the separation is a parameter. Luminosities, radii and colours follow main-sequence scalings; no tides or mass transfer.
Equations used in the module
Equations a₁/a₂ = M₂/M₁; P² = a³/(M₁+M₂); M₁v₁ = M₂v₂
