Tidal Dissipation inside close-in super-Earths coupled with its Thermal and Orbital evolution

Since the first detection of exoplanets in 1995, dozen close-in planets including planets with several Earth mass have been detected. More and more Earth-sized close-in planets will also be detected in the next decades through ongoing space telescope missions such as Kepler. Tidal dissipation within interior of such a close-in planet plays an important role on thermal evolution and internal structure of a planet because it works as a heat source, as well as on the evolution of orbital eccentricity and semi-major axis. On the other hand, tidal dissipation rate depends on the planetary internal structure, such as the relative proportion of solid and gas and its thermal state. Thus, the evolution of orbit and internal structure (or thermal state) should be coupled via tidal dissipation, which varies with time. However, the effect of tidal dissipation on planetary internal structure is still uncertain though the internal structure of exoplanets have been energetically investigated. From this standpoint, we have investigated tidal dissipation of close-in super Earths taking into account both thermal and orbital evolution. In our model, the radial distribution of tidal dissipation within planetary interior is calculated taking into account the solid-liquid phase diagram of silicate rocks. In the presentation, we will review the previous study on the tidal dissipation of Jovian- and Saturnian satellites, and discuss how the tidal dissipation influences on the internal structure of super-Earths.