  The detection and atmospheric characterization of super-Earths is one of the
major frontiers of exoplanetary science. Currently, extensive efforts are
underway to detect molecules, particularly H2O, in super-Earth atmospheres. In
the present work, we develop a systematic set of strategies to identify and
observe potentially H2O-rich super-Earths that provide the best prospects for
characterizing their atmospheres using existing instruments. Firstly, we
provide analytic prescriptions and discuss factors that need to be taken into
account while planning and interpreting observations of super-Earth radii and
spectra. We discuss how observations in different spectral bandpasses constrain
different atmospheric properties of a super-Earth, including radius and
temperature of the planetary surface as well as the mean molecular mass, the
chemical composition and thermal profile of the atmosphere. In particular, we
caution that radii measured in certain bandpasses can induce biases in the
interpretation of the interior compositions. Secondly, we investigate the
detectability of H2O-rich super-Earth atmospheres using the HST WFC3
spectrograph as a function of the planetary properties and stellar brightness.
We find that highly irradiated super-Earths orbiting bright stars, such as 55
Cancri e, present better candidates for atmospheric characterization compared
to cooler planets such as GJ 1214b even if the latter orbit lower-mass stars.
Besides being better candidates for both transmission and emission
spectroscopy, hotter planets offer higher likelihood of cloud-free atmospheres
which aid tremendously in the observation and interpretation of spectra.
Finally, we present case studies of two super-Earths, GJ 1214b and 55 Cancri e,
using available data and models of their interiors and atmospheres.

Earth and Planetary Astrophysics