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The 10 October 1999 HIP 9369 occultation by the northern polar region of Jupiter: ingress and egress lightcurves analysis |
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| Authors: | E Raynaud P Drossart B Sicardy F Roques GR Gladstone D Nadeau R Doyon MJ Rieke |
| Institution: | a LESIA, CNRS-FLE2461, Observatoire de Paris, 5 place Janssen, 92195 Meudon Cedex, France b Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092, USA c Southwest Research Institute, 6220 Culebra Road, P.O. Drawer 28510, San Antonio, TX 78228-0510, USA d Atmospheric, Oceanic, and Space Science Department, University of Michigan, 2455 Hayward, Ann Arbor, MI 48109-2143, USA e Observatoire du Mont Mégantic et Département de Physique, Université de Montréal, C.P. 6128, Montréal H3C 3J7, Canada f Steward Observatory, University of Arizona, Tucson, AZ 85721-0065, USA g Astronomy Department, New Mexico State University, Las Crucas, NM 88003-8001, USA |
| Abstract: | The occultation of bright star HIP9369 by the northern polar region of Jupiter was observed from four locations in North and South America, providing four data sets for ingress and egress. The inversion of the eight occultation lightcurves provides temperature profiles at different latitudes ranging from 55°N to 73.2°N. We estimate the errors on the profiles due to the uncertainties of the inversion method and compare the value of the temperature at the deepest level probed (∼ 50 μbar) with previous observations. The shape of the temperature gradient profile is found similar to previous investigations of planetary atmospheres with propagating and breaking gravity waves. We analyze the small scale structures in both lightcurves and temperature profiles using the continuous wavelet transform. The calculated power spectra of localized fluctuations in the temperature profiles show slopes close to −3 for all eight profiles. We also isolate and reconstruct the three-dimensional geometry of a single wave mode with vertical and horizontal wavelengths of respectively 3 and 70 km. The identified wave is consistent with the gravity wave regime, with a horizontal phase speed nearly parallel to the planetary meridian. Nevertheless, the dissipation of the corresponding wave in Jupiter’s stratosphere should preclude its detection at the observed levels and an acoustic wave cannot be ruled out. |
| Keywords: | Jupiter Occultations Atmospheres Dynamics Atmospheres Structure |
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