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The First Transiting Super- Earths

Within the research field of exoplanets, we have now formally entered the realm of super-Earths with the discoveries of CoRoT- 7b and GJ1214b reported last year.These are the first of many low-mass detections to come in the near future. The first step into characterizing this type of planets is to infer their composition from the available data: masses, radii, orbital distances and irradiation values. I will present results on the structure and composition of these two planets. Owing to the degenerate character of inferring composition, we provide limits to the compositional end- members ( amount of H/He , H20, silicate mantles and iron cores).This information needs to then to reconciled with a formation and evolutionary scenario, thus providing further constraints. While we favor a rocky composition forCoRoT-7b (it has a density of 5.6 g/cc), the presence of an envelope of water vapor above a terrestrial nucleus cannot be discarded. By exploring the fate of its atmosphere we argue that it could have formed as a terrestrial planet or as a giant planet that subsequently suffered atmospheric stripping due to the intense irradiation. Instead, fof GJ1214b's, we find it is a mini-Neptune.  We show that given it's mass ( of 6.55 earth-masses) and equilibrium temperature, its size indicates the presence of H/HE.