2014 April 30

Cyclonic ovals add interest to final part of Jupiter apparition

David Arditti

Jupiter’s particularly favourable (for UK observers) high northerly declination apparition of this year is drawing to a close. While many observers will now be concentrating their attention on Mars, and on Saturn further to the east, we would encourage attempts still to observe and image Jupiter in the western sky. In daylight, infra-red imaging with a monochrome camera can yield very good results with Jupiter still so high.

In the last few months a development of particular interest has been the evolution of new spots in the South South Temperate Belt (the dark region of Jupiter’s atmosphere south of the Great Red Spot.) These are cyclonic circularions, in contrast to the long-lived white spots in these latitudes, which are anticyclonic. The most prominent of them has been a white oval juxtaposed between two closely-spaced anticyclonic spots (known as A3 and A4, see map) but slightly north of them, earning the formation the monicker “Mickey Mouse ears” from its appearance in south at top images. Recently this oval has appeared to flatten.

Other new cyclonic features have been a reddish oval between anticyclonic ovals A7a and A8 and a lighter reddish area between ovals A0 and A1. It is of interest to see if these develop into full-blown white cyclonic ovals over time. It appears that these cyclonic ovals appear as cells when anticyclonic ovals converge rapidly, and resist the merger of the anticyclonic ovals, pushing them apart again, but more study, and more observations, are needed to discover if these are consistent patterns.

The remarkable Jupiter apparition of 2013/14 is in its final stages now, but it is worth persisting with observations of the giant planet, as valuble data is still there to be gleaned on these developments.