Ph.D. defense by Lars A. Buchhave – Niels Bohr Institute - University of Copenhagen

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Ph.D. defense by Lars A. Buchhave

Detecting and Characterizing Transiting Extrasolar Planets 


We live in an exciting time in astronomy: We are poised to answer some of mankind's fundamental questions, such as: Is the Solar system unique, or are Earth-like planets, where life might be comfortable, common in our galaxy? Can we uncover spectroscopic signatures in exoplanet atmospheres suggesting the existence of life elsewhere in the Universe? Fifteen years ago, no planet outside our Solar system had been discovered. Since then, over 500 exoplanets have been found, the vast majority of which are quite unlike those in our own Solar System and unlike any that had been predicted by theory. Today, we are on the brink of discovering planets and planetary systems similar to our own and determining how frequently Earth-like planets orbit stars in our galaxy.

A unique opportunity for characterizing an exoplanet exists when the planet transits its host star and thus dims its light slightly: We can infer the planet's exact mass and radius, its bulk density and chemical composition, its temperature and age, and the dynamics of the system. Further observations even allow the study of their atmospheres. This is the kind of physical information needed to inform the next generation of theories to explain the great diversity of observed exoplanets, and transiting planets are being discovered in great numbers from ground-based surveys and dedicated space missions, such as the European CoRoT and NASA's Kepler mission.

The focus of this project is to develop and use efficient spectroscopic techniques for studying transiting exoplanet candidates to confirm their planetary nature and characterize their properties. I have closely collaborated with and am a member of three of the world's premier photometric transit surveys: NASA's Kepler mission and the ground-based the MEarth and HATNet surveys. My work has helped to discover and characterize a significant number of true transiting planets, including one of the first transiting super-Earths, the first multi-transiting planetary system containing a possible planet with a radius 1.6 times that of the Earth, and a number of hot-Jupiter planets with surprising properties.

Johannes Andersen

Followed by a reception in the DARK Lounge, Rockefeller Komplekset, Juliane Maries Vej 30.