J. Lecacheux and P. Drossart, Meudon Observatory; F. Colas, Bureau des Longitudes; G. Orton and B. Fisher, Jet Propulsion Laboratory; A. Sanchez-Lavega, R. Hueso, and J. F. Rojas, University of Pais Vasco; and I. Miyazaki write: "Jupiter's 58- year-old white ovals known as BC and DE are now a single white oval located at planetographic latitude -34 deg. Pic-du-Midi observations in the red continuum on 1998 Jan. 17 show a distinct, very close pair of ovals, but infrared observations made with the NASA Infrared Telescope Facility on Mar. 27 (after Jupiter emerged from solar conjunction) show only a single oval. This aspect was confirmed via red and methane-band (890-nm) filters obtained since May 7 at Pic-du-Midi. The new oval 'BE' drifts at a rate of -0.20 deg/day relative to the System III rotation rate of the interior, and the oval's corresponding longitude can be represented (from data May 7-June 6) by 10338.2 deg - 0.2025 deg (JD - 2400000). Extrapolation of the new oval position back to the 1997 Dec.-1998 Jan. time frame places it at the location of BC, but further observations are needed the better to constrain the dynamics of the new oval. The collision event took place in Feb. 1998, when Jupiter was close to conjunction. The visible and infrared images show the new oval 'BE' larger by about 20 percent than either BC or DE was. White oval FA is unchanged, drifting at a rate of -0.158 deg/day and separated westward from 'BE' by 24 deg on June 12."
International Astronomical Union Circular
- Pub Date:
- June 1998