= Solution
A <super-Earth> is a planet more massive than Earth but below the usual ice-giant scale, conventionally \b[about $1$--$10M_\oplus$]. The term does not guarantee an Earth-like or rocky composition; water-rich planets and objects with small H/He envelopes can lie in this range.
The most direct constraints are transit radius and a mass from radial velocities or <transit-timing variations>, giving $\bar\rho=3M/(4\pi R^3)$. Comparing these with interior models constrains the possible iron core, silicate mantle, <water> layer and gas envelope, but many mixtures share one mass and radius.
Additional observables include atmospheric spectra/<mean molecular weight> and escape signatures, which test whether a low-density envelope is H/He or heavier volatiles; stellar Fe/Mg/Si abundances as priors on refractory composition; and age, irradiation and orbital history, which control thermal expansion and envelope survival. Where measurable, a <Love number> or related apsidal response constrains central concentration. \b[Mass and radius constrain families of interiors, not a unique composition]; atmospheric and dynamical information can reduce this <exoplanet interior-composition degeneracy>.
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