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Welcome, my name is Phil, and in this video I explain how the mass of exoplanets can be calculated.

The orbit and radius of an exoplanet can be determined by the transit method, but it can not be used to find the exoplanets mass. The radial velocity method can be used to calculate the mass. Here, the wobble of the the star can be measured using the doppler shift in light of the star. Assuming that the orbit is circular, Kepler's 3rd law can then be used to find the semi-major axis and orbital velocity of the exoplanet, which can then be used to find the mass.