The transit method is a photometric method that can indirectly detect the presence of one or more exoplanets in orbit around a star. One example of the use of this method, is to detect M51-ULS-1b. This method is related to the brightness of the stars, this is because when this brightness decreases, it is significant because there is an exoplanet between the earth and this star. And through this formula, we can detect the radius of this exoplanet and more information.
This is an example of how Exoplanet Transit Methods works
The Doppler spectroscopy (also known as the radial-velocity method) is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star.
This is an example of how Radial Velocity Doppler Spectroscopy Method of Exoplanets works
We can solve the formula of the velocity with this: v = c × Δλ/λ
where λ is the wavelength emitted by the source, Δλ is the difference between λ and the wavelength measured by the observer, c is the speed of light, and v is the relative speed of the observer and the source in the line of the vision.
