 For example, if the measured radial velocity is low, this can mean that the true orbital velocity is low (implying low mass objects) and the inclination high (the orbit is seen edge-on), or that the true velocity is high (implying high mass objects) but the inclination low (the orbit is seen face-on).The peak radial velocity formula_1 is the semi-amplitude of the radial velocity curve, as shown in the figure.The orbital period formula_2 is found from the periodicity in the radial velocity curve.