Astrometric Exoplanet Detection: The Star's Wobble on the Sky

Most exoplanet-hunting techniques you'll see visualized — transits, radial velocity — infer a planet indirectly from a dip in brightness or a Doppler shift. Astrometry is more direct: it measures the star itself moving, tracing a tiny reflex loop around the system's barycenter as its unseen planet tugs it around. This simulator renders that reflex orbit in 3D to true relative scale, alongside the planet's own orbit, and computes the real numbers an astrometric survey like Gaia would report — the angular wobble amplitude in microarcseconds, the orbital period from Kepler's third law, and a live verdict on whether the signal would clear Gaia's detection threshold. Adjust planet mass, star mass, orbital distance and system distance to see which combinations produce a wobble large enough to catch, and which vanish into the noise floor.