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The Cassini spacecraft's imaging cameras were designed to photograph nearby bodies in the Saturn system, but they were turned towards Jupiter on February 8, 2007.
This image shows The white and brown cloud bands of Jupiter, when the planet was more than 11 times the distance between Earth and the Sun, or slightly farther than the average Earth-Saturn distance.

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Credit NASA/JPL/Space Science Institute

Images taken using red, green and blue spectral filters were combined to create this natural colour view. The images were taken with the Cassini spacecraft narrow-angle camera at a distance of approximately 1.8 billion kilometres from Jupiter and at a Sun-Jupiter-spacecraft, or phase, angle of 50 degrees. Scale in the original image was about 10,000 kilometres per pixel.

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On February 24, 2007, the LEISA infrared spectral imager in the New Horizons Ralph instrument observed giant Jupiter in 250 narrow spectral channels. At the time the spacecraft was 6 million kilometres from Jupiter; at that range, the LEISA imager can resolve structures about 400 kilometres across.
That may seem large, mission scientists say, but Jupiter itself is more than 144,000 kilometres across.

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Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

"The detail revealed in these images is simply stunning. Our instrument is performing spectacularly well" - Dr. Dennis Reuter, Ralph/LEISA project scientist and a New Horizons co-investigator from NASA's Goddard Space Flight Center in Greenbelt, Md.

LEISA observes in 250 infrared wavelengths, which range from 1.25 micrometers (µm) to 2.50 µm. The three images shown above from that dataset are at wavelengths of 1.27 µm (left), 1.53 µm (centre) and 1.88 µm (right).

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NASA's Hubble Space Telescope Monitors Jupiter in Support of the New Horizons Flyby
NASA's Hubble Space Telescope took this true-colour view of Jupiter in support of the New Horizons Mission. The image was taken with Hubble's Wide Field Planetary Camera 2 on February 17, 2007, using the planetary camera detector. Jupiter's trademark belts and zones of high- and low-pressure regions appear in crisp detail. Circular convection cells can be seen at high northern and southern latitudes. Atmospheric features as small as 400 km across can be discerned.

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Credit NASA

NASA's Hubble Space Telescope has recently taken images of Jupiter in support of the New Horizons Mission. The images were taken with Hubble's Wide Field Planetary Camera 2 and the Advanced Camera for Surveys. Hubble will continue to photograph Jupiter, as well as its volcanically active moon, Io, over the next month as the New Horizons spacecraft flies past Jupiter. New Horizons is en route to Pluto, and made its closest approach to Jupiter on February 28, 2007. Through combined remote imaging by Hubble and in situ measurements by New Horizons, the two missions will enhance each other scientifically, allowing scientists to learn more about the Jovian atmosphere, the aurorae, and the charged-particle environment of Jupiter and its interaction with the solar wind.
For one photo, the combined ultraviolet- and visible-light images of Jupiter were taken with Hubble from February 17-21. The image segments in the boxes, obtained using the Advanced Camera for Survey's ultraviolet camera, show auroral emissions that are always present in Jupiter's polar regions. The equatorial regions of Jupiter were imaged in blue light by the Wide Field Planetary Camera 2. Cloud features in Jupiter's main atmosphere are revealed. In the ultraviolet views, the atmosphere looks more hazy because sunlight is reflected from higher in the atmosphere.

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On February 28, 2007, NASA's New Horizons spacecraft made its closest approach to Jupiter on its ultimate journey to Pluto. This flyby gave scientists a unique opportunity to study Jupiter using the package of instruments available on New Horizons, while coordinating observations from both space- and ground-based telescopes including NASA's Chandra X-ray Observatory.
In preparation for New Horizon's approach of Jupiter, Chandra took 5-hour exposures of Jupiter on February 8, 10, and 24th. In this new composite image, data from those separate Chandra's observations were combined, and then superimposed on the latest image of Jupiter from the Hubble Space Telescope.

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Credit: X-ray: NASA/CXC/SwRI/R.Gladstone et al.; Optical: NASA/ESA/Hubble Heritage (AURA/STScI)

The purpose of the Chandra observations is to study the powerful X-ray auroras observed near the poles of Jupiter. These are thought to be caused by the interaction of sulphur and oxygen ions in the outer regions of the Jovian magnetic field with particles flowing away from the Sun in the so-called solar wind. Scientists would like to better understand the details of this process, which produces auroras up to a thousand times more powerful than similar auroras seen on Earth.
Following closest approach on the 28th, Chandra will continue to observe Jupiter over the next few weeks. New Horizons will take an unusual trajectory past Jupiter that takes it directly down the so-called magnetic tail of the planet, a region where no spacecraft has gone before. The sulphur and oxygen particles that dominate Jupiter's magnetosphere and originate in Io's volcanoes are eventually lost down this magnetic tail. One goal of the Chandra observations is to see if any of the X-ray auroral emissions are related to this process.
By combining Chandra observations with the New Horizons data, plus ultraviolet information from NASA's Hubble Space Telescope and FUSE satellite, and optical data from ground-based telescopes, astronomers hope to get a more complete picture of Jupiter's complicated system of particles and magnetic fields and energetic particles. In the weeks and months to come, astronomers will undertake detailed analysis of this bounty of data.

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This image of Jupiter is produced from a 2x2 mosaic of photos taken by the New Horizons Long Range Reconnaissance Imager (LORRI), and assembled by the LORRI team at the Johns Hopkins University Applied Physics Laboratory. The telescopic camera snapped the images during a 3-minute, 35-second span on February 10, when the spacecraft was 29 million kilometres from Jupiter. At this distance, Jupiter's diameter was 1,015 LORRI pixels - nearly filling the imager's entire (1,024-by-1,024 pixel) field of view. Features as small as 290 kilometres are visible.

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Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Both the Great Red Spot and Little Red Spot are visible in the image, on the left and lower right, respectively.

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Jupiter's aurorae
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Title: A study of Jupiter's aurorae with XMM-Newton
Authors: G. Branduardi-Raymont (1), A. Bhardwaj (2), R. F. Elsner (3), G. R. Gladstone (4), G. Ramsay (1), P. Rodriguez (5), R. Soria (6 and 1), J. H. Waite Jr (7), T. E. Cravens (8) ((1) Mullard Space Science Laboratory, University College London, Holmbury St Mary, UK, (2) Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum, India, (3) NASA Marshall Space Flight Center, Huntsville, USA, (4) Southwest Research Institute, San Antonio, USA, (5) XMM-Newton SOC, Villafranca, Spain, (6) Harvard-Smithsonian Center for Astrophysics, Cambridge, USA, (7) University of Michigan, Ann Arbor, USA, (8) Department of Physics and Astronomy, Lawrence, USA)

We present a detailed analysis of Jupiter's X-ray (0.2-10 keV) auroral emissions as observed by XMM-Newton in Nov. 2003 and compare it with that of an Apr. 2003 observation. We discover the existence of an electron bremsstrahlung component in the aurorae, which accounts for essentially all the X-ray flux above 2 keV: its presence had been predicted but never detected for lack of sensitivity of previous X-ray missions. This bremsstrahlung component varied significantly in strength and spectral shape over the 3.5 days covered by the Nov. 2003 observation, displaying substantial hardening of the spectrum with increasing flux. This variability may be linked to the strong solar activity taking place at the time, and may be induced by changes in the acceleration mechanisms inside Jupiter's magnetosphere. As in Apr. 2003, the auroral spectra below 2 keV are best fitted by a superposition of line emission most likely originating from ion charge exchange, with OVII playing the dominant role. We still cannot resolve conclusively the ion species responsible for the lowest energy lines (around 0.3 keV), so the question of the origin of the ions (magnetospheric or solar wind) is still open. It is conceivable that both scenarios play a role in what is certainly a very complex planetary structure. High resolution spectra of the whole planet obtained with the XMM-Newton RGS in the range 0.5-1 keV clearly separate emission lines (mostly of Fe) originating at low latitudes on Jupiter from the auroral lines due to O. These are shown to possess very broad wings which imply velocities of ~5000 km/s. Such speeds are consistent with the energies at which precipitating and charge exchanging O ions are expected to be accelerated in Jupiter's magnetosphere. Overall we find good agreement between our measurements and the predictions of recent models.

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Jupiter's Little Red Spot Growing Stronger
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The highest wind speeds in Jupiter's Little Red Spot have increased and are now equal to those in its older and larger sibling, the Great Red Spot, according to observations with NASA's Hubble Space Telescope.
The Little Red Spot's winds, now raging up to approximately 400 miles per hour, signal that the storm is growing stronger, according to the NASA-led team that made the Hubble observations. The increased intensity of the storm probably caused it to change colour from its original white in late 2005, according to the team.
Although it seems small when viewed against Jupiter's vast scale, the Little Red Spot is actually about the size of Earth, and the Great Red Spot is around three Earth diameters across. Both are giant storms in Jupiter's southern hemisphere powered by warm air rising in their centres.
The Little Red Spot is the only survivor among three white-coloured storms that merged together. In the 1940s, the three storms were seen forming in a band slightly below the Great Red Spot. In 1998, two of the storms merged into one, which then merged with the third storm in 2000. In 2005, amateur astronomers noticed that this remaining, larger storm was changing colour, and it became known as the Little Red Spot after becoming noticeably red in early 2006.
The new Hubble observations by the team reveal that winds in the Little Red Spot have grown stronger compared to previous observations. In 1979, Voyager 1 and 2 flew by Jupiter and recorded that top winds were only about 268 miles per hour in one of the "parent" storms that merged to become the Little Red Spot. Nearly 20 years later, the Galileo orbiter revealed that top wind speeds were still the same in the parent storm, but winds in the Great Red Spot blew at up to 400 miles per hour. The team used Hubble's new Advanced Camera for Surveys instrument to discover that top wind speeds in both storms are now the same, because this instrument has enough resolution to track small features in these storms, revealing their wind speeds.
Scientists are not sure why the Little Red Spot is growing stronger. One possibility is a change in size. These storms naturally fluctuate in size, and their winds spin around their central core of rising air. If the storm were to become smaller, its spiralling winds would increase the same way spinning ice skaters turn faster by pulling their arms closer to their bodies. Another possibility is that it's the only survivor.

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Great Red Spot
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Astronomers from the University of California, Berkeley, and the W. M. Keck Observatory in Hawaii this month snapped high-resolution near-infrared images of the Great Red Spot, a persistent, high-pressure storm on Jupiter, as a smaller storm, Red Spot Jr., breezed by it on its race around the planet.

The image, which also shows Jupiter’s moon Io, was taken on July 20 Hawaii time (July 21 Universal Time) by the Keck II telescope on Mauna Kea using adaptive optics (AO) to sharpen the image.
The spots are of interest to astronomers because Red Spot Jr. formed from the merger of three white spots only recently, between 1998 and 2000, and in December 2005 turned red like the much older Great Red Spot. While the new red spot is about the size of Earth, the Great Red Spot is nearly twice that diameter and has been circling the planet for at least 342 years.
The images captured by the second-generation Near Infrared Camera (NIRC2) on Keck II show that, though the two red spots are about the same colour when seen in visible wavelengths (see Christopher Go’s optical image from July 20 UT), they differ markedly at infrared wavelengths. When the astronomers viewed the planet through a narrow-band filter centred on the 1.58 micron, near-infrared wavelength, Red Spot Jr., which was called Oval BA before it changed from white to red, was a lot darker, indicating that the tops of the storm clouds may be lower than those of the Great Red Spot. With more atmosphere above its cloud tops, more infrared light is absorbed by molecules like methane in the atmosphere.

"Red Spot Jr. is either not as high as the Great Red Spot, or it’s just not as reflective, that is, as dense. These images will put some constraints on the altitude of Red Spot Jr." - astronomer Imke de Pater, professor of astronomy at UC Berkeley.

The Great Red Spot is thought to tower about 8 kilometres above the surrounding cloud deck. The fact that Red Spot Jr. turned red may indicate its swirling storm clouds are rising higher also, though apparently they are not as high as those of its larger companion, or the clouds are thinner.

Why the spots are red is a subject of great debate. Some people think the hurricane-like winds in the Great Red Spot, which can reach 400 miles per hour, dredge up material from deeper in the planet’s atmosphere that, when exposed to ultraviolet light, turns red. One candidate is phosphine gas, PH3, which has been detected on Jupiter. Ultraviolet light might catalyse its conversion to red phosphorus, P4, according to one of the leading theories. Other, more complicated theories have phosphine interacting in the atmosphere with chemicals such as methane or ammonia to form complex compounds such as methylphosphane or phosphaethyne.
Recent studies suggest that the red colour also may be attributed to sulphur allotropes, that is, different molecular configurations, including chains and rings, of pure sulphur, such as S3-S20. The new work hypothesizes that ammonium hydrosulphide particles are carried upwards in the Great Red Spot and are broken up by ultraviolet light. Subsequent chemical reactions ultimately lead to long-chained sulphur allotropes , which can vary in colour from red to yellow.

"The jury is still out on the exact processes that lead to the red coloration of the Great Red Spot – and Oval BA" - Imke de Pater.

Christopher Go, an amateur astronomer who first noticed the coloration change of Red Spot Jr., joined de Pater’s team earlier this year. He noted that during the close encounter between the two spots, Red Spot Jr. was squashed slightly, stretching in its direction of motion. The same thing happened in 2002 and 2004 when the Great Red Spot and Red Spot Jr. passed one another, though then Junior was white.
The Great Red Spot rotates westward, opposite to the eastward rotation of the planet. Because alternating bands on the Jovian surface move in opposite directions, the adjacent Red Spot Jr. moves eastward. The planet rotates about once every 10 hours.
Another of de Pater’s colleagues, UC Berkeley mechanical engineering professor Philip Marcus, predicted several years ago that Jupiter’s climate was changing, based on the disappearance of the cyclonic storms or spots within the bands. The mixing of the atmosphere by these cyclones keeps the temperature about the same over the entire planet, he argued, so loss of this mixing will cause the equator to heat up and the poles to cool.
Earlier this year, on April 16, de Pater and her team captured near-infrared, ultraviolet and visible light photos of the planet using the Hubble Space Telescope to look more closely at the two red spots. The observations with the Keck Telescope were a follow-up study to try to measure the speeds of the swirling winds in the spots. Jupiter’s brightness, however, confused the adaptive optics system, forcing the astronomers to miss some good shots of the planet as the guide star was being positioned optimally relative to Jupiter.



"This was probably the most challenging observation ever tried with the AO system at Keck" - Imke de Pater, referring to use of the laser guide star system next to an object as bright as Jupiter.

Adaptive optics can take the twinkle out of an object caused by thermal motion in the atmosphere, but to do this well, the target must be near another bright object that can serve as a reference. For some of the images, Jupiter’s moon Io was used as the reference “star.” But until Io got close enough for this, a laser guide star was created near Jupiter to serve this purpose.

"This was our first attempt using the laser to obtain AO-corrected images of Jupiter’s surface. The technique shows promise and, if we perfect it, will provide us with many more opportunities to observe this fascinating, ever-changing object" - Dr. Al Conrad, a support astronomer at the Keck Observatory.

The team also obtained a close-up of the two spots through a narrow-band filter centred on 5 microns, which samples thermal radiation from deep in the cloud layer. Both spots appear dark because the clouds completely block heat emanating from lower elevations, though narrow regions around the spots that are devoid of clouds show leakage of this heat out into space.

"These 5 micron images reveal details in the cloud opacity not seen at the other wavelengths and will help unravel the vertical structure of the spots. The smooth, narrow arcs visible to the south of each spot probably result from the interaction between the spots and high-speed winds that are deflected around them" - Michael Wong, UC Berkeley team member.

The resolution using both the narrow and wide views on the camera was about 0.1 arcseconds, or only half as good as can be obtained on a clear night with optimal seeing.

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RE: Jupiter
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A high-resolution image released today by the Gemini Observatory shows Jupiter's two giant red spots brushing past one another in the planet's southern hemisphere.

The image was obtained in near-infrared light using adaptive optics which corrects, in real-time, for most of the distortions caused by turbulence in Earth's atmosphere. The result is a view from the ground that rivals images from space.



In the near-infrared, the red spots appear white rather than the reddish hue seen at visible wavelengths.

"It was tricky getting this image. Since we used adaptive optics we needed a star-like object nearby to guide on, so we had to find a time when Jupiter's moon Io would appear close enough to Jupiter and the red spots would be optimally placed on Jupiter's disk. Fortunately it all worked out on the evening of July 13th and we were able to capture this relatively rare set of circumstances" Chad Trujillo, Gemini astronomer who helped lead the effort to capture the event.

Both red spots are massive storm systems. The top of the larger one, known for a long time as the Great Red Spot, lies about 8 kilometres above the neighbouring cloud tops and is the largest hurricane known in the solar system. The smaller storm (officially called Oval BA, but informally known as Red Spot Junior) is another hurricane-like system. Since it appears nearly as bright as the Great Red Spot in near-infrared images, Red Spot Junior may be at a similar height in the Jovian atmosphere as the Great Red Spot.
Red Spot Junior is roughly half the size of its famous cousin, but its winds blow just as strong. This mighty new storm formed between 1998 and 2000 from the merger of three long-enduring white ovals, each a similar storm system at a smaller scale, which had been observed for at least 60 years. But it was not until February 27th of this year that Philippine amateur astronomer Christopher Go discovered that the colour of the newly formed white oval had turned brick red. Astronomers were witnessing the birth of a new red spot.

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Red Spot Jr.
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The Hubble Space Telescope is giving astronomers their most detailed view yet of a second red spot emerging on Jupiter. For the first time in history, astronomers have witnessed the birth of a new red spot on the giant planet, which is located half a billion miles away. The storm is roughly one-half the diameter of its bigger and legendary cousin, the Great Red Spot. Researchers suggest that the new spot may be related to a possible major climate change in Jupiter's atmosphere.


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The left image was acquired on April 8, 2006 with Hubble's Advanced Camera for Surveys (high-resolution channel). It shows that the second red spot has a small amount of pale clouds in the centre. A strong convective event, which is likely a thunderstorm, is visible as a bright white cloud north of the oval, in the turbulent clouds that precede the Great Red Spot. As the oval continues its eastward drift and the Great Red Spot moves westward, they should pass each other in early July. This contrast-enhanced image was taken in blue and red light. The group that performed this observation was led by Amy Simon-Miller (NASA Goddard Space Flight Centre), Glenn Orton (Jet Propulsion Laboratory) and Nancy Chanover (New Mexico State University).

The right image, of the entire disk of Jupiter, was acquired on April 16, 2006 by Hubble's Advanced Camera for Surveys (wide field channel). The second red spot appears at southern latitudes, below the centre of Jupiter's disk. The new spot is approximately the size of Earth's diameter. The image was taken in visible light and at near-infrared wavelengths, and does not represent Jupiter's true colours. The red colour traces high-altitude haze blankets: the equatorial zone, the Great Red Spot, the second red spot, and the polar hoods. The Hubble group that conducted this observation is led jointly by Imke de Pater (UCB Astronomy) and Philip Marcus (UCB Mechanical Engineering). Other team members are Michael Wong (UCB Astronomy), Xylar Asay-Davis (UCB Mechanical Engineering), and Christopher Go, an amateur astronomer with the Astronomical League of the Philippines.



Dubbed by some astronomers as "Red Spot Jr.," the new spot has been followed by amateur and professional astronomers for the past few months. But Hubble's new images provide a level of detail comparable to that achieved by NASA's Voyager 1 and 2 spacecraft as they flew by Jupiter a quarter-century ago.

Before it mysteriously changed to the same colour as the Great Red Spot, the smaller spot was known as the White Oval BA. It formed after three white oval-shaped storms merged during 1998 to 2000. At least one or two of the progenitor white ovals can be traced back to 90 years ago, but they may have been present earlier. A third spot appeared in 1939. (The Great Red Spot has been visible for the past 400 years, ever since earthbound observers had telescopes to see it).

When viewed at near-infrared wavelengths (specifically 892 nanometers — a methane gas absorption band) Red Spot Jr. is about as prominent in Jupiter's cloudy atmosphere as the Great Red Spot. This may mean that the storm rises miles above the top of the main cloud deck on Jupiter just as its larger cousin is thought to do. Some astronomers think the red hue could be produced as the spots dredge up material from deeper in Jupiter's atmosphere, which is then chemically altered by the Sun's ultraviolet light.
Researchers think the Hubble images may provide evidence that Jupiter is in the midst of a global climate change that will alter its average temperature at some latitudes by as much as 10 degrees Fahrenheit. The transfer of heat from the equator to the planet's south pole is predicted to nearly shut off at 34 degrees southern latitude, the latitude where the second red spot is forming. The effects of the shut-off were predicted by Philip Marcus of the University of California, Berkeley (UCB) to become apparent approximately seven years after the White Oval collisions in 1998 to 2000.

Two teams of astronomers were given discretionary time on Hubble to observe the new red spot.

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