What crucial physical characteristic can be calculated when both the radius (from transit) and mass (from radial velocity) of a planet are known?

Answer

Density.

Combining the planet's radius derived from transit data and its mass derived from radial velocity data allows astronomers to calculate its density, which is essential for inferring its composition (rocky versus gaseous).

What crucial physical characteristic can be calculated when both the radius (from transit) and mass (from radial velocity) of a planet are known?
measurementastronomyexoplanetsdetection