> From jhr11@hermes.cam.ac.uk Sun Dec 8 07:25 MST 2002 Date: Sun, 8 Dec 2002 14:23:50 +0000 (GMT) From: "J.H. Rogers" Subject: Jupiter: S.S. Temperate ovals Hi, Jupiter team: Ovals in the S.S. Temperate region: more mergers? The attached chart shows the history of white spots in the S.S. Temperate domain over the past year, and the attached image montage shows their appearance in the last two months. A year ago there were 7 small anticyclonic white ovals (AWOs) in the S.S. Temperate domain at 40-41 deg.S; they have existed for several years and have gradually bunched together so that they were all within 160 deg. longitude. I have labelled them as A1 to A7; some of them were separated by cyclonic white ovals at about 39 deg.S which are labelled C. (There may have been one or two more, even smaller, spots.) In 2002 March, AWOs A7 and A6 merged, an event that amateur observers tracked in detail. The chart suggests that the merged oval merged with A5 in turn, during solar conjunction, as there are only 5 AWOs now present. A consequence is that the whole series of ovals is still converging. This sequence of mergers was strikingly similar to the sequential mergers of similar but larger white ovals in the S. Temperate domain in recent years - FA with DE and then with BC. In each case the oval at highest longitude has proceeded to lower longitudes merging with other ovals in turn. However oval A3 may also be involved in mergers and hi-res observations of it would be very worthwhile from now on. (It can be seen in many images from a year ago as oval A3 was passing the GRS on 2002 Jan.1.) The images in Oct. and Nov. show A3 to have a variable, lobed structure, as if it were merging with another white oval. One possibility is that it was merging with oval A2, and that the oval presently named A2 on the chart is a new one. In any case, the present oval A2 is rapidly converging on A3 and compressing the cyclonic white oval that lies between them. Possibly they will rebound (as suggested by the latest image), or possibly they will merge within the coming weeks, as they pass the GRS. John Rogers, Hans-Joerg Mettig, Damian Peach. British Astronomical Association > From sherrodc@ipa.net Sun Dec 8 08:20 MST 2002 From: "Clay Sherrod" Subject: Re: Jupiter: S.S. Temperate ovals Date: Sun, 8 Dec 2002 09:18:09 -0600 Hello John, Hans and Damian... As usual John, fantastic work and resource on these spots. Getting to where we cannot see the forest for the numerous trees in the southern hemisphere and this definitely helps. It is an incredibly interesting carrousel of movement throughout the southern temperate areas on Jupiter right now and the spots are gaining in both number and brightness in my opinion. There have been many "transient" or short-lived spots, some of which have taken on a dull gray color and not gained the intensity of these longer-lived features; the activity and rapid morphological change of these features relative to one-another strongly suggests eddy currents, as does the increasing activity in longitudes preceding the GRS as well. I look forward to continued observations of this area.....we have several series of these ovals from the last two mornings posted under the ASO Planet Patrol section at www.arksky.org but unfortunately are looking for several consecutive days of bad weather. Thanks again to all........ Clay ---------------------------------------- Dr. P. Clay Sherrod sherrodc@ipa.net Arkansas Sky Observatory MPC/cbat Obs. H43 www.arksky.org > From dpeach_78@yahoo.co.uk Sun Dec 8 12:18 MST 2002 Date: Sun, 8 Dec 2002 19:18:53 +0000 (GMT) Subject: Re: Jupiter: S.S. Temperate ovals Hi John, Thanks for the fascinating analysis - it hadnt occured to me that another oval merger may have occured during solar conjunction, but the charts seem to suggest it. In the latest Dec 7th images, the array remains prominent, but the small STZ bright spot bordering AWO2 seems to be fading out. Also, many thanks to Clay for your supply of detailed images. The array of NEBn barges at L2-240 is quite striking. Best Wishes Damian