Next-generation ground- and space-based infrared telescopes will be capable of measuring the atmospheric compositions of smaller and cooler planets than Spitzer or Hubble. It is critical that we understand the limitations of future instruments in order to maximize the science returns from these low-signal sources. To that end, we look to the lessons learned from moderating systematics in Spitzer data of one of the most observed, published, and highest signal-to-noise exoplanets: HD 209458 b. We analyzed all Spitzer transits and eclipses of HD 209458 b with our Photometry for Orbits, Eclipses, and Transits code (POET), fit a Keplerian orbit with RadVel, and performed an atmospheric retrieval with our Bayesian Atmospheric Radiative Transfer code (BART). Looking toward future exoplanet observatories, we use modified versions of ExoSim to model future planned and proposed ground- and space-based instruments with high detail, including various realistic systematics and noise sources. These simulations will inform upcoming observing strategies, and new simulations can be readily applied to additional observatories.
Spitzer was operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Exoplanets Research Program grant NNX17AB62G and NASA Astrophysics Data Analysis Program grant NNX13AF38G.