The Ultimate Spitzer Phase Curve Survey: Empirical Trends from a Uniform Analysis

Although exoplanetary sciences were not projected to be a substantial part of its original mission, investigation of exoplanets with Spitzer has set the stage for future exploration with JWST. Spitzer pioneered a powerful technique consisting of observations spanning the full orbit of an exoplanet to reveal the longitudinal temperature structure of the planet. Embedded in thermal phase curves of exoplanets are constraints on the atmospheric structure and dynamics that continue to propel future investigations. With over 30 Spitzer phase curves of hot Jupiters spanning a wide range of equilibrium temperatures and orbital configurations, the complete data set provides an unprecedented opportunity to identify trends in the properties of hot Jupiter atmospheres. We present a uniform reduction and analysis of all 4.5 μm phase curves to minimize variations caused by using different approaches. We test theoretical and empirical trends with a large uniform sample of phase curves and conclude with how to move forward with spectroscopic phase curve observations in the era of JWST and the Ariel mission launching later this decade.