The GEMINI/GMOS optical transmission spectral survey of close-in gas giant exoplanets

Estimating the nature and abundances of chemical species and clouds in exoplanetary atmospheres forms the backbone of comparative exoplanetology. We present a long-term ground-based survey of a dozen transiting hot Jupiters observed in the visible bandpass using the Gemini Multi-Object Spectrograph (GMOS). By observing transits of an ensemble of hot Jupiters spanning a range of masses, radii, and host star types, and using a consistent methodology for extracting their transmission spectra across the sample, we derive common properties for their atmospheres. We present the main results of this survey, the challenges faced by such an experiment, and the lessons learned for future MOS observations and instrument designs. Ultimately, this survey aims at improving our understanding of the diversity of physical processes at play in exoplanetary atmospheres.