2002/10/31 by Kristen Menou, James Y‐K. Cho, James Y-K. Cho +3
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/375015
published as Astrophys.J. 587 (2003) L113-L116 · 6 pages, 1 table, 1 figure. Accepted for publication in ApJL
arxiv created 2003/03/12 · openalex publication_date 2003/03/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
Shallow-water numerical simulations show that the atmospheric circulation of the close-in extrasolar giant planet (EGP) HD 209458b is characterized by moving circumpolar vortices and few bands/jets (in contrast to ~10 bands/jets and the absence of polar vortices on cloud-top Jupiter and Saturn). The large spatial scales of moving circulation structures on HD 209458b may generate detectable variability of the planet's atmospheric signatures. In this Letter, we generalize these results to other close-in EGPs, by noting that shallow-water dynamics is essentially specified by the values of the Rossby (Ro) and Burger (Bu) dimensionless numbers. The range of likely values of Ro (~10 -2 to 10) and Bu (~1-200) for the atmospheric flow of known close-in EGPs indicates that their circulation should be qualitatively similar to that of HD 209458b. This results mostly from the slow rotation of these tidally synchronized planets.