A team of astronomers from NASA’s Goddard Space Flight Center, the agency’s Jet Propulsion Laboratory, and the University of California, Berkeley, has produced two global maps of Jupiter using the Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope. The maps are the first in a series of annual portraits of the Solar System’s outer planets – Jupiter, Uranus, Neptune and Saturn – from the Outer Planet Atmospheres Legacy (OPAL) Program.
This global map of Jupiter was made during the Hubble OPAL Program. The map was observed on 19 January 2015, from 2:00 UTC to 12:30 UTC. Image credit: NASA / ESA / A. Simon, GSFC / M. Wong, University of California, Berkeley / G. Orton, JPL-Caltech.
This global map of Jupiter was made during the Hubble OPAL Program. The map was observed on 19 January 2015, from 15:00 UTC to 23:40 UTC. Image credit: NASA / ESA / A. Simon, GSFC / M. Wong, University of California, Berkeley / G. Orton, JPL-Caltech.
The two maps represent nearly back-to-back rotations of Jupiter, making it possible to determine the speeds of the planet’s winds, to identify different phenomena in its atmosphere and to track changes in its most famous features.
Data for the maps were taken during the Hubble OPAL Program observations of the gas giant on January 19, 2015, from 2:00 UTC to 12:30 UTC (first map) and from 15:00 UTC to 23:40 UTC (second map).
“Every time we look at Jupiter, we get tantalizing hints that something really exciting is going on. This time is no exception,” said Dr Amy Simon of NASA’s Goddard Space Flight Center.
The maps confirm that Jupiter’s most famous feature – the spinning, cyclone-like storm known as the Great Red Spot – continues to shrink, but that it may not go out without a fight.
The Great Red Spot has been decreasing in size at a noticeably faster rate from year to year for some time. But now, the rate of shrinkage seems to be slowing again, even though the spot is still about 150 miles (240 km) smaller than it was in 2014.
The storm remains more orange than red these days, and its core, which typically has more intense color, is less distinct than it used to be.
At the center of the storm, an unusual wispy filament can be seen spanning almost the entire width of the vortex.
This filamentary streamer rotates and twists throughout the ten-hour span of the Great Red Spot image sequence, distorted by winds that are blowing at 330 miles per hour (150 m per second).
Just north of Jupiter’s equator, astronomers have found a rare wave structure, of a type that has been spotted on the planet only once before, decades ago by the Voyager 2 mission, which was launched in 1977.
In the Voyager 2 images the wave was barely visible and scientists began to think its appearance was a fluke, as nothing like it has been seen since, until now.
The current wave was found in a region dotted with cyclones and anticyclones. Similar waves – called baroclinic waves – sometimes appear in the Earth’s atmosphere where cyclones are forming.
“Until now, we thought the wave seen by Voyager 2 might have been a fluke. As it turns out, it’s just rare,” said Dr Glenn Orton of NASA’s Jet Propulsion Laboratory.
The wave may originate in a clear layer beneath the clouds, only becoming visible when it propagates up into the cloud deck.
These findings are described in a new paper published online in the October issue of the Astrophysical Journal.
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Amy A. Simon et al. 2015. First results from the Hubble OPAL Program: Jupiter in 2015. ApJ 812, 55; doi: 10.1088/0004-637X/812/1/55