Mass of the transiting secondary companion as a function of radial velocity perturbation on the primary. The mass of the secondary is constrained by the transit depth, using a main sequence stellar mass-radius relation (red lines), and by the radial velocity amplitude of the primary, assuming a circular Keplerian orbit (blue lines). The mathematical K_RV –M₂ relation is also shown, with an uncertainty range reflecting the uncertain mass of the primary (black lines).