[10]  SEB revival outbreak (report, 2007 June 20th)

Here is a chart* showing the motion of the dark spots on SEB(S) – the southern branch of the SEB Revival.

The retrograding motion is very clear, and typical for a SEB Revival.  The speeds in L2 are: (a) +120; (b,c) +110; (d,e) +84 (degrees per 30 days).  These speeds for (a,b,c) are typical of the SEBs jet, and we reported speeds in the same range in 2000/01 and 2001/02. 

The spots retrograded more slowly when they were close to the source (~ +55 to +80 deg/month); some were also notably large and southerly.  Both of these properties might have been due to the adjacent STrD-2, but they were not well correlated, so they may have been simply the properties of recently-created spots. 

STrD-1 is at L2 = 325, slowly prograding (L3 = 213).  The leading dark spot (a) is on course to encounter it on July 1.  If STrD-1 still exists with a strong enough circulating current, spot (a) will flip round and might travel back in the opposite direction, in the STBn jet (or it might be torn apart).  If STrD-1 is not strong enough, spot (a) will carry on retrograding, though probably with reduced speed.  Therefore, it is important to get images of STrD-1 from July 1 onwards as frequently as possible – preferably on every rotation during the first week in July. 

Also attached is a set of images of the SEB Revival outbreak on June 18, when it was well imaged on 3 successive rotations.

*Notes on the chart:

These longitude measurements were made manually by JHR, from images by Carvalho, Chang, Fattinanzi, Ghomizadeh, Go, Haese, Ikemura, Fukui, Jakiel, Lomeli, Medugno, Miyazaki, Olivetti, Parker, & Akutsu.

Some of the scatter may be due to inaccuracies in timing of a few images.

Dark spots on SEB(S) are labelled (a) to (f): (a) Leading dark spot, (b-e) other dark spots, (f) little red spot.  The different types of crosses do not mean anything, but particularly large, southerly spots are circled.

A S.S.Temperate white oval was measured as a reference point.

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John Rogers,
Jupiter Section Director,
British Astronomical Association.