Atmospheric Circulation of Exoplanets

Abstract

We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from Solar-System studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric dynamics are given particular attention, as these close-in planets have been the subject of most of the concrete developments in the study of exoplanetary atmospheres. We then turn to the basic elements of circulation on terrestrial planets as inferred from Solar-System studies, including Hadley cells, jet streams, processes that govern the large-scale horizontal temperature contrasts, and climate, and we discuss how these insights may apply to terrestrial exoplanets. Although exoplanets surely possess a greater diversity of circulation regimes than seen on the planets in our Solar System, our guiding philosophy is that the multi-decade study of Solar-System planets reviewed here provides a foundation upon which our understanding of more exotic exoplanetary meteorology must build.

In EXOPLANETS, edited by S. Seager, to be published in the Spring of 2010 in the Space Science Series of the University of Arizona Press (Tucson, AZ) (refereed; accepted for publication)

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Cited by in corpus (23)

• Disequilibrium Carbon, Oxygen, and Nitrogen Chemistry in the Atmospheres of HD 189733b and HD 209458b
• Exoplanet Atmospheres
• Stabilizing Cloud Feedback Dramatically Expands the Habitable Zone of Tidally Locked Planets
• The climate of HD 189733b from fourteen transits and eclipses measured by Spitzer
• Orbital Phase Variations of the Eccentric Giant Planet HAT-P-2b
• The atmospheric circulation of a nine-hot Jupiter sample: Probing circulation and chemistry over a wide phase space
• Atmospheric dynamics of brown dwarfs and directly imaged giant planets
• Magnetic Scaling Laws for the Atmospheres of Hot Giant Exoplanets
• Photometric and Spectral Signatures of 3D Models of Transiting Giant Exoplanets
• The rotational and divergent components of atmospheric circulation on tidally locked planets
• Connecting the dots II: Phase changes in the climate dynamics of tidally locked terrestrial exoplanets
• Gliese 581g as a scaled-up version of Earth: atmospheric circulation simulations
• Equatorial anti-rotating day side wind flow in WASP-43b elicited by deep wind jets?
• The Effect of Orbital Configuration on the Possible Climates and Habitability of Kepler-62f
• Chemical variation with altitude and longitude on exo-Neptunes: Predictions for Ariel phase-curve observations
• Mapping Directly Imaged Giant Exoplanets
• Radiation-Hydrodynamics of Hot Jupiter Atmospheres
• Convective dynamics and disequilibrium chemistry in the atmospheres of giant planets and brown dwarfs
• Nonequilibrium thermodynamics of circulation regimes in optically-thin, dry atmospheres
• Saturn Ring Seismology: Looking Beyond First Order Resonances
• The Trouble with Water: Condensation, Circulation and Climate
• Point vortex dynamics in three-dimensional ageostrophic balanced flows
• Exploring the Diversity of Jupiter-Class Planets (Discussion Meeting Contribution)