Jupiter At Infrared Wavelengths
Date: 22 July 1997
Copyright: ESA/ISO, ISOCAM & Th. Encrenaz et al.
The video consists of 86 frames shown at a rate of 2.5 frames per second. Each frame is at a different wavelength between 2.3 and 11.6 microns, as indicated by the moving pointer. North is at the top. The images were obtained sequentially over 35 minutes. During that time the Great Red Spot, seen conspicuously bright below the equatorial at the outset moves a little to the right.
At the outset and in other early frames ISO sees the cloudy zones of Jupiter and the Great Red Spot.
Around 3.3 microns the planet goes dramatically dark because methane gas in the atmosphere absorbs all the infrared radiation.
At 5 microns, ISO sees deep into the atmosphere, in the belts between the cloud zones. The bright spots conspicuous north of the equator are hot dry regions, similar to the one visited by the Galileo probe.
Around 7.7 microns, ISO is looking at the upper atmosphere (stratosphere) of Jupiter. The south polar region glows bright.
In the last images, Jupiter is becoming too hot for the camera The rate of frequency change is not constant. Thus 3 microns is attained at frames 15-16, 4 microns at 31-32, 5 microns at 44-47, 6 microns at 54-55, 7 microns at 63-64, 8 microns at 69-70, 9 microns at 74-75, 10 microns at 82-83, and 11 microns at 87-88.
ISOCAM operated with an image scale of 1.5 seconds of arc per pixel in the circular variable filter mode. The equator of Jupiter spans about 30 pixels