Topic summary
True Mass

Extracted from the Wikipedia article Minimum mass.
Radial velocity method
The term true mass is synonymous with the term mass, but is used in astronomy to differentiate the measured mass of a planet from the minimum mass usually obtained from radial velocity techniques. Methods used to determine the true mass of a planet include measuring the distance and period of one of its satellites, advanced astrometry techniques that use the motions of other planets in the same star system, combining radial velocity techniques with transit observations (which indicate very low orbital inclinations), and combining radial velocity techniques with stellar parallax measurements (which also determine orbital inclinations).