Friday 26 Jun 2015Seminar: Low-Resolution Optical Transmission Spectroscopy of Exoplanet Atmospheres

Dr Catherine Huitson - University of Colorado

Physics, 4th floor 14:00-15:00

As a planet passes in front of its host star, light from the star is filtered through the planet's atmosphere, revealing absorption lines characteristic of the atmospheric composition. This is the planet's transmission spectrum. At low resolution, broad spectral features can be identified in the optical transmission spectrum revealing the presence of molecular features from species such as atomic Na I and K I as well as signatures of cloud scattering.

I present the first ground-based low-resolution transmission spectra survey, aimed at a homogeneous and comparative study of multiple exoplanets. Our work makes use of the Gemini telescopes and GMOS multi-object optical spectroscopy, which builds on current results obtained from space. The use of ground-based telescopes has allowed us to widen the studied sample above previous studies. The aim is to move towards an understanding of global atmospheric properties and how they tie in to physical causes such as stellar irradiation, type and planetary equilibrium temperature. I will detail our motivations, methodology, challenges faced and first results.

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