A large and rapidly growing body of observations is unveiling the meteorology on giant exoplanets that are exotic compared to Jupiter, Saturn, Uranus, and Neptune. The best characterized planets are the close-in hot Jupiters, but planets that are smaller and farther from their stars are also slowly coming into focus. Observational constraints include infrared lightcurves (indicating homogenization of the temperature by winds in some cases, but not others), dayside spectra, radius measurements, upper limits on visible albedo, and several constraints on composition. These observations hint at a wide range of behaviors among different planets. Here, I will review the diversity of atmospheric circulations (and observational implications) expected on giant planets ranging from our local giants to hot Jupiters and hot Neptunes. I will summarize relevant basic dynamics, discuss expected trends, and address highlights of open questions including the following: What determines the day-night temperature difference and mode of heat transport? What controls whether a planet exhibits a banded structure? Should the circulation on hot Jupiters (and its thermal/visible signature) exhibit temporal variability? What are the possible regimes of cloud formation -- should cloud decks (if any) be global, dayside-only, nightside-only, or something else entirely? How should the circulation on hot Neptunes differ from that on hot Jupiters? How is circulation influencd by a high orbital eccentricity (leading to factor-of-several starlight variations throughout the planet's orbit)? How might the circulation be affected by planetary mass, gravity, rotation rate, distance from the star, and metallicity? The goal is to sketch the broad picture and identify the implications for existing and future observations.
AAS/Division for Planetary Sciences Meeting Abstracts #39
- Pub Date:
- October 2007