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TOPIC: Titan


L

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RE: Titan
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Using an instrument on board the Cassini orbiter, a black lake-like feature in the south polar region of Saturn's moon, Titan, has been shown to be truly wet.

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L

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Titan T-45 fly-by
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Cassini Titan (T-45) fly-by
The Cassini spaceprobe flyby (altitude = 1591 km)  will measure Titan's gravity field to probe the interior of Titan and confirm the existence of subsurface oceans on July 31st, 2008.

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L

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RE: Titan
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A team of astronomers has used infrared spectral images of Saturns moon, Titan, acquired with the Gemini North Frederick C. Gillett Telescope, to dispute an earlier claimed detection of widespread morning methane drizzle.
Titan, the second largest moon in the solar system, has long fascinated astronomers because it is the only moon in the solar system with a thick atmosphere. Adding to the fascination, its cold atmosphere (94 K or -180º C near the surface) has a number of interesting similarities to our Earths atmosphere. For example, its complex temperature profile (temperature vs. altitude) has the same overall structure as Earths and the atmospheric surface pressures are nearly the same. Also like the earths atmosphere, nitrogen is the dominant chemical species.
After nitrogen, methane is the most abundant chemical species in Titans atmosphere. It has sometimes been said that methane plays the same role in Titans atmosphere as water does in ours.

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L

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T44 Flyby
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T44 Flyby of Titan on May 28, 2008.
This flyby will approach to a distance of only 1,400 km above the surface of the moon.
The Cassini spaceprobe will image the  anti-Saturnian hemisphere of Titan and  include imagery of Xanadu.
This will be the last flyby of the original four-year tour. An  extended mission, named the "Saturn Equinox Mission," will start this summer, a two-year odyssey with 26 Titan flybys, 7 Enceladus encounters, and one flyby each of the icy moons Dione, Rhea and Helene.

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RE: Titan
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This side-by-side view shows a newly discovered impact crater (left) compared with a previously discovered crater (right). The new crater was just discovered by the Cassini spacecraft's radar instrument during its most recent Titan flyby on May 12, 2008. This makes the fourth feature definitely identified as an impact crater so far on Titan -- fewer than 100 features are regarded as possible impacts.

titantec2a
Expand (411kb, 1280 x 960)
Credit: NASA/JPL

Both images are about 350 kilometres in width. The crater on the right was discovered by Cassini in 2005 and is shown here for comparison. It is 80 kilometres in diameter, with the radar illumination from above. Called Sinlap, this crater is estimated to be about 1,300 metres deep. The new feature pictured on the left, which has not been named yet, is bigger than the Sinlap crater with a diameter of about 112 kilometres.
The new crater is located at about 26 degrees north latitude, 200 degrees west longitude, in the bright region known as Dilmun, about 1,000 kilometres north of the Huygens landing site.

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A set of three parallel ridges was seen by the Cassini spacecraft's radar instrument during the latest Titan flyby on May 12, 2008. This combination is unlikely to be a coincidence -- the best explanation for these features is that they are tilted or separated blocks of broken or faulted crust, now exposed as high ridges. Their regular spacing is typical of regions that have been compressed or extended over large areas.

titantec2
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Credit: NASA/JPL

Along the south sides of the ridges are prominent cliffs, or scarps, present as thin, radar-dark lines trending west-to-east, and interpreted as faults. These features are dark due to shadowing from the radar illumination, and have heights up to a few hundred metres, based on preliminary estimates of slopes.
The area shown here is located in the mountainous region called Xanadu.
The image is centred at 2 degrees south, 127 degrees west and was obtained on May 12, 2008.

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L

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Titan T43 flyby
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Cassini is on a course for a Titan flyby on May 12, at an altitude of 1,000 kilometres, for the first of two Titan northern hemisphere flybys that will wrap up the prime mission.
On this flyby, Cassini's radar will map the bright region of Xanadu, which was only partly imaged previously. This overlap in coverage may yield stereo views of the region. The radar team has targeted Hotei Arcus, as well as a possible cryovolcanic feature, Tortola Facula (informally known as the 'Snail'), which was visible in infrared images.

Source NASA

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RE: Titan
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Normalement, les effets de marée exercés sur les satellites naturels par leur planète, sont assez forts pour freiner la rotation des satellites, et l'immobiliser dans une rotation synchrone, où le satellite présente toujours la même face à sa planète (c'est le cas de la Lune par exemple). La sonde Cassini vient d'observer pour Titan une rotation super-synchrone, et plusieurs hypothèses sont avancées pour en rendre compte. Des astronomes de l'IMCCE de l'Observatoire de Paris font partie d'une équipe qui propose que la mesure de la vitesse de rotation est faussée.
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Titan and Earth have much in common, but not when it comes to sand.
On Earth, sand grains form by breaking things down, but on Titan, the opposite may be true - with much of the sand a product of building things up.
That's one theory Cassini scientists are considering after studying Titan's massive sand dunes with the visible and infrared mapping spectrometer on the Cassini Saturn orbiter. The new observations raise the possibility that much of the sand grows from hydrocarbon particulates fallen from the sky that, once on the ground, join together and become sand grain-size particles.

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The image is the first topographic map of part of Titan's north polar region.
The false-colour mosaic on the left was produced from overlapping stereo images from the Cassini radar instrument and depicts Titan's north polar region including several of its largest "seas." The mosaic (see Titan's North Polar Region for a larger version) has been false-coloured to emphasise the contrast between radar-dark areas believed to be lakes and seas (shown in blue and black) and the relatively radar-bright dry land areas (shown in shades of brown). The material filling the dark areas is most likely a mixture of liquid methane, ethane and dissolved nitrogen.

titae1
Expand (75kb, 1024 x 256)
Credit: NASA/JPL/Space Science Institute

The two "knife-shaped" images to the right are actually blowups of a region in the mosaic of radar images outlined in blue. This region is 1,700 by 200 kilometres in area.


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