Following over two decades of discoveries, we now have a substantial sample of exoplanets that can be characterized in detail with current facilities, enabling the emerging field of comparative exoplanetology. Studies of hot Jupiters at low spectral resolution have revealed a rich diversity of planetary atmospheres that range from cloudy to cloud-free, and exhibit scattering slopes from aerosols and absorption features from species such as Na, K, and TiO.
On the other hand, high-spectral-resolution observations are emerging as a particularly powerful and robust probe of exoplanetary atmospheres. High-resolution observations can also place strong constraints on the abundances, altitudes, and local temperatures where each species forms. Atmospheric winds, structure, and planetary rotation can also be measured using high-resolution observations
In this talk, I will present an overview and preliminary results of the Gemini-N Large and Long Program ‘Exploring the Diversity of Exoplanet Atmospheres at High Spectral Resolution’ (PI: Jake Turner). Our survey will advance the field by carrying out the first comparative study of exoplanet atmospheres at high spectral resolution with Gemini-N/GRACES. The use of high-resolution spectroscopy, where we can uniquely identify atoms and molecules, distinguishes our survey from other comparative studies. In total, we will survey ~45 planets over the course of our survey. To date, we have taken observations of 11 exoplanets. The planets observed so far span a large range of planetary equilibrium temperatures, from 680–2100 K, planetary masses, from 0.7 Neptune mass to 2.4 Jupiter mass, and planetary sizes, from 4.2 Earth radii to 2 Jupiter radii. With a broad spectral range of 400-1050 nm, our observations can probe atomic species such as Na, K, Fe, Mg, and Ca and molecular species such as TiO, VO, and H2O.
In summary, our survey will advance our understanding of the diversity of exoplanet atmospheres in significant ways, and shed new light on how this diversity depends on the physical properties of the planets and their host stars.