Currently, we can only measure data that allows us to infer the radius, orbit, and sometimes mass of an exoplanet— not a lot of information to work with and certainly not enough to understand the geophysical properties of a planet, like its composition.

My paper uses changes in orbits as a proxy for bounces. If a planet rapidly changes its orbit, it dissipates energy quickly and is thus more rock-like. We can use these deviations to calculate tidal Q values for exoplanets and look for how many are super-Earths and how many are sub-Neptunes!