Atmospheric characterization of rocky to giant exoplanets in thermal emission with JWST

 All life we know lives on Earth, a rocky planet orbiting a G-type star. Thousands of planets orbiting nearby stars have been discovered in the past decades, ranging from small terrestrial planets to massive gas giants. Atmospheric characterization of these planets will provide us with key insights into their formation mechanisms and potential for habitability. The launch of JWST, the new NASA flagship space telescope capable of unprecedented infrared precision photometric and spectroscopic capabilities has been and will be the main science driver for exoplanet atmospheric characterization in this decade and the next.

The main science themes of this conference will be focused on: 

(1) Understanding the thermal structure and atmospheric composition of gas giant planets in the context of their formation and evolution histories

Gas giants make up most of the mass of any planetary system, thus their formation and evolution pathways dominate the planetary system architecture. Emission spectra of gas giant planets reveal their atmospheric thermal structure and composition. Measuring the temperature of the planetary deep interiors is a direct way to probe the thermal evolution history of the planet. The chemical composition and elemental abundance ratios of the atmosphere are informative in determining the formation location and accretion process within the protoplanetary disk.

(2) Search for evidence of atmospheres on rocky planets around M-dwarf stars

M-dwarfs are the most common type of star in the universe and represent 75% of all stars in the Milky Way. The number of rocky planets per M-dwarf has been measured from Kepler and TESS missions to be the same, if not larger, than the number of rocky planets per FGK star. Therefore, most of the rocky planets in our galaxy orbit M-dwarfs. If life can exist on these planets, they could represent where most life in the universe resides. The presence of an atmosphere is likely a strict prerequisite for the presence of life. M-dwarfs are usually much more active compared to our Sun with frequent stellar flares and high extreme ultraviolet and x-ray emissions. The harsh stellar radiation environments may strip away the atmosphere on small rocky planets. It is currently unknown if these rocky planets around M-dwarf can retain an atmosphere and JWST planetary thermal emission measurement is one of the best observational tools we have to answer that question. 500 hours of JWST was just recommended in the most recent cycle to answer this question via measuring the thermal emission of rocky exoplanets.