The mega-cyclone dance around Jupiter poles
Orderly groups of giant cyclones, thousands of kilometres large, dance around Jupiter poles. They have been discovered by an international team, guided by Alberto Adriani (IAPS-INAF) with the participation of researcher of ISAC-CNR and ASI, through the analysis of the images acquired by the JIRAM (Jovian InfraRed Auroral Mapper) instrument on board the NASA satellite Juno.
“With the very accurate infrared images acquired by JIRAM, we discovered for the first time this complex configuration in the north and south polar regions of Jupiter – says Alberto Adriani, scientific P.I. of JIRAM and first author of the Nature paper – In particular there are two stable cyclones located on each pole, surrounded by swirling structures resembling a wreath around them.”
Eight cyclones surround the northern polar cyclone, while five surround the southern one, all of them of similar sizes. The extension of these cyclones is enormous, their diameter being close to the Earth’s radius: in Jupiter north pole they can be as large as 4 thousands of kilometres while in the south pole they are larger than 6 thousands of kilometres. Even the wind speed internal to these atmospheric structures is very high, in the range of 150 to 350 kilometres per hour.
“In the observations acquired by JIRAM so far, we have evidence that these structures are stable – adds Alberto Adriani– so stable to block the slow drift toward the poles of the cyclonic structures that form at lower latitudes.”
Never before the polar regions of the largest planet of the Solar System have been observed. Juno satellite has been able to obtain this result due to its injection into a polar orbit around Jupiter and to the very advanced instruments on board. Among them there is JIRAM, a sort of infrared ‘camera’ capable to observe both the auroral and thermal emissions of the planet. The instrument is totally Italian, thought and designed by the Italian team author of the paper, built by Leonardo S.p.A and funded by ASI.
The analysis of JIRAM data reported in the paper is also due to a collaboration between the INAF team and two researchers of ISAC-CNR, Maria Luisa Moriconi and Bianca Maria Dinelli, that have supported Adriani’s team with their expertise on the atmosphere: “The exploitation of the experience gained on the Earth’s atmosphere has enabled the interpretation of the data acquired on Jupiter polar regions” comments Bianca M. Dinelli.
The work is published on Nature in the paper Clusters of cyclones encircling Jupiter’s poles by A. Adriani, A. Mura, G. Orton, C. Hansen, F. Altieri, M. L. Moriconi, J. Rogers, G. Eichstädt, T. Momary, A. P. Ingersoll, G. Filacchione, G. Sindoni, F. Tabataba-Vakili, B. M. Dinelli, F. Fabiano, S. J. Bolton, J. E. P. Connerney, S. K. Atreya, J. I. Lunine, F. Tosi, A. Migliorini, D. Grassi, G. Piccioni, R. Noschese, A. Cicchetti, C. Plainaki, A. Olivieri, M. E. O’Neill, D. Turrini, S. Stefani, R. Sordini e M. Amoroso