Report on the NTB outbreak (June 2012.)
outbreak on NTBs jet-stream
the last week of the 2011/12 apparition, a major new outbreak started on the
largely-faded North Temperate Belt (NTB).
We have been expecting such an outbreak this year, as explained at:
on the recent acceleration of the jet back to super-fast speeds at cloud-top
level, and the 5-year periodicity of such outbreaks from 1970 to 1990.
(The last such outbreak was in 2007.)
following alert was sent out (2012 April 25):
Kardasis has just sent the attached images, from April 19, noting the very dark
spot on the NTBs, with a bright spot preceding it.
This is very likely a new outbreak on the super-fast NTBs jet-stream!
Confirmation is urgently needed!
There was nothing there in his image of this longitude on April 12, nor
in the few other images that I have seen from recent weeks (by H. Einaga and L.
Obviously Jupiter is now too close to the Sun for good-quality imaging
but if anyone can get any images of these longitudes, even in daylight, or can
send images from recent days, please do so....”
on the super-fast jet, the bright spot should move with DL1 ~ -5 deg/day (DL3 ~
-13 deg/day), while the dark streak would elongate behind it and become
turbulent, as observed in 1990 and 2007. From
the size of the dark streak, it probably began about a week before the first
2012 April 19, 17:19 UT, the bright spot was at L1 =75 (L3 = 336), followed by a
very dark streak from L1 = 79 to 99.
On April 21, 18:39 UT, Gianluigi Adamoli fortuitously managed to record
these features: probable bright spot at L1 ~ 64, dark streak from L1 = 70 to 91,
consistent with the expected drifts.
There were no further images of the longitude of the bright spot, but
images on April 26 (by Manos Kardasis and John Rozakis and Antonio Lasala)
recorded the f. end of a very dark segment at L1 ~ 90. No further useful images
were obtained after that date, in spite of observers’ efforts, as the planet
went behind the Sun. All the data indicate that a typical super-fast outbreak
had begun, but it was frustratingly impossible to determine accurate speeds or
to resolve the features.
is therefore vitally important to get images as soon as possible after solar
It may be possible to confirm the outbreak by obtaining drift rates for
residual spots, and/or by finding a revived NTB(S), initially turbulent and
These are typical sequels of the super-fast outbreak that are not
recorded in any other circumstances.
credit is due to the observers, especially Manos Kardasis, for persevering under
such difficult circumstances and discovering this important event, which could
so easily have been missed.
Images of the start of the NTBs outbreak, 2012 April.
John H. Rogers, Ph.D. Jupiter Section Director,
British Astronomical Association