What spectral Fingerprints of Exoplanets reveal


A decade of exoplanet search has led to surprising discoveries, from
giant planets close to their star, to planets orbiting two stars, all
the way to the first extremely hot, rocky worlds with potentially
permanent lava on their surfaces due to the star's
proximity. Observing mass and radius alone can not break the
degeneracy of a planet's nature due to the effect of an extended
atmosphere that can also block the stellar light and increase the
observed planetary radius significantly.  Even if a unique solution
would exist, planets with similar density, like Earth and Venus,
present very different planetary environments in terms of habitable
conditions. Therefore the question refocuses on atmospheric features
to characterize a planetary environment and what the spectra of an
exoplanet can reveal.