Binary Orbits: Two-Body Dance
draft readiness: experimental Orbits Both 12 min
Core demo behavior is implemented, but parity and launch-gate signoff are still pending.
If the embed doesn’t load, open the demo fullscreen.
Predict
Predict
If one star is much more massive than the other, where is the center of mass located?
Play
Play
- Adjust mass ratio and watch the barycenter shift (the heavier body moves less).
- Change separation $a$ and observe how the period $P$ changes.
- Compare an equal-mass case to an unequal-mass case using Station Mode snapshot rows.
Explain
Explain
Explain how the center of mass helps you understand the motion of both bodies.
Learning goals
- Describe how two masses orbit a shared center of mass.
- Predict how changing mass ratio affects orbital motion.
- Connect orbital behavior to the idea of gravitational interaction.
Misconceptions targeted
- The larger object stays fixed while the smaller one orbits it.
Model notes
- This pilot assumes perfectly circular orbits and point masses (no eccentricity, tides, or relativity).
- Units: distance in $\mathrm{AU}$, time in $\mathrm{yr}$, and masses in $M_{\odot}$. This instrument takes $M_1 = 1\,M_{\odot}$ and sets $M_2$ via the mass-ratio slider; it uses the teaching normalization $G = 4\pi^2\,\mathrm{AU}^3/(\mathrm{yr}^2\,M_{\odot})$.
About this demo
This pilot demo visualizes two masses orbiting a shared barycenter. It emphasizes qualitative relationships (how the barycenter shifts and how the period changes with separation) rather than modeling a specific astrophysical binary.