Bonn 2010 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 11: Exoplanets
EP 11.3: Talk
Wednesday, March 17, 2010, 15:45–16:00, AKM
Structure and Composition of the CoRoT-7b Exoplanet — •Frank W. Wagner, Frank Sohl, Hauke Hussmann, Heike Rauer, and Matthias Grott — Institute of Planetary Research, German Aerospace Center, Berlin, Germany
The field of planetary sciences is rapidly expanding due to the growing number and unexpected diversity of discovered planets beyond the solar system. CoRoT-7b is the first exoplanet among more than a dozen low-mass (<15 M⊕) extrasolar planets for which the radius and mass have been accurately determined. In units of Earth equivalents, these are 1.68±0.09 R⊕ (Léger et al. 2009) and 4.8±0.8 M⊕ (Queloz et al. 2009), respectively. The average compressed density of CoRoT-7b of 5.6±1.3 Mg m−3 is comparable to the Earth’s (5.515 Mg m−3) and suggests a terrestrial-type bulk composition. We model the internal structure of CoRoT-7b as a type example for a terrestrial extrasolar planet using mass and energy balance constraints. Our results suggest that CoRoT-7b may represent a dry, rock-rich planet predominantly composed of silicates, similar to the Earth’s Moon (Wagner et al. 2009). An iron-rich core at depth would be small and less massive or even non-existent, suggesting that CoRoT-7b may have originated in the iron-depleted region beyond the snowline and lost its volatile mass fraction when subsequently moving toward its primary.
Acknowledgments This research is supported by the Helmholtz Alliance "Planetary Evolution and Life".