Methods for detecting exoplanets include the Doppler shift method, observing the Doppler effect on a star's spectrum; the Transit method, noting periodic dimmings in a star's brightness; Gravitational lensing, measuring light bending from distant stars; and observing disturbances in a star's dust disk.
There are several methods for detecting planets outside our solar system, known as exoplanets. The Doppler shift method involves observing the Doppler effect on a star's spectrum to detect its radial velocity and any wobble caused by the gravitational tug of an orbiting planet. This can manifest as tiny redshifts or blueshifts in the spectral lines as the star moves toward or away from us, respectively, due to an orbiting planet's influence.
The Transit method relies on detecting slight, periodic dimmings in a star's brightness as a planet transits or crosses in front of it. Repetitive transits can confirm the presence of an exoplanet by determining its orbital period and calculating the planet's size based on the amount of dimming.
Other techniques include Gravitational lensing, where the gravity of a star and its planet can bend the light of a more distant star that passes behind it, temporarily magnifying the distant star's light in a detectable way. Astrometric detection measures tiny changes in a star's position in the sky caused by an orbiting planet. Additionally, the presence of planets can also be inferred from disturbances in a star's dust disk.