Titan Images 2018

The three views of Titan's disk above, originally released on February 10, 2006, correspond to mosaics mostly revealing landscape features of the Opaque Moon. The mosaics were produced on the basis of data obtained from the Visual and Infrared Mapping Spectrometer of the Cassini spacecraft during the flybys of the giant moon performed on October 28, 2005 (left disk), December 26, 2005 (middle disk) and January 15, 2006 (right disk). The mosaics are made of artificial colors and are based on images acquired at the following wavelengths : 1.6 microns for the blue color, 2.01 microns for the green color and 5 microns for the red color. The viewing geometry of the flyby performed in December appears approximately on the opposite hemisphere of the Opaque Moon from that obtained in the flybys of October and January.
One can notice, in particular, that the south polar cloud system appears very bright and seems relatively active during the flyby of Titan carried out in December. By contrast, the south polar cloud system appears barely visible and weak during the flybys performed in October and January. One can infer that the atmosphere is particularly dynamic over the south polar region. In the mosaic of December, one can also notice a bright patch or a hood over the north polar region. The composition of that patch which appears bright at 5 microns is unknown. The bright feature engulfing the north polar region can be barely seen in the data captured from the orbiter during the flyby of October (left view) and during the flyby of January (right view).
In the views of October and January, one can clearly observe a bright patch just south of the equator. That patch represents a particular region of Titan which is known as Tui Reggio and which is nicknamed the  chevron . That feature appears very bright at 5 microns and is among the brightest areas on Saturn's largest moon at that wavelength. Tui Reggio is believed to be composed of a surface deposit related to cryovolcanism. The presumed cryovolcano may have produced a vapor of water and/or carbon dioxide. Is Tui Reggio composed of a mixture of frozen water and frozen carbon dioxide ? The data taken during the flyby of January reveal that the western margins of that bright area unveil a complex network of channels likely related to eruptive phenomena or cryovolcanism.

Image Credit: NASA/JPL/University of Arizona.

 

The image in the upper part of the table unveils six views of the globe of Titan in the infrared spectrum on the basis of data obtained from the Visual and Infrared Mapping Spectrometer (VIMS) during the long mission of the Cassini spacecraft from 2004 to 2017. The global views of Saturn's largest moon reveal the surface of the icy world and appear clear and without any seam thanks to a meticulous work aiming at combining the multitude of VIMS data of the Opaque Moon taken under different lighting and viewing conditions during the Cassini mission. Previous VIMS maps of the giant moon were made of clear seams between different areas of the landscape due to a significant variation in imaging resolution and lighting conditions. The new global views of Titan's surface don't show any seam and appear natural. Therefore, they represent the best global views of Titan we have ever unveiled in the infrared spectrum.
Let's point out that the Titanian atmosphere appears opaque in the visible spectrum but in the infrared spectrum, that is not the case anymore. There is a smog or a haze in Titan's atmosphere which prevents us from discerning surface features from outer space in the visible spectrum. The upper atmosphere of the Orange Moon generates aerosols which strongly scatter visible radiations. As a result, the surface of the giant moon can be clearly seen in a few infrared  windows . Thus, the surface can be clearly observed in infrared wavelengths where scattering and absorption are much weaker. The VIMS instrument had the correct filters to clearly image Titan's surface. Producing mosaics of Titan with VIMS data is far from being an easy task since the images were taken over numerous flybys with various observing geometries and atmospheric conditions. That's why seams naturally appear in the mosaics. But the specialists managed to remove most of the seams thanks to laborious and detailed analyses of the different views. It took a lot of time and a lot of work to produce this series of global views.
The color view is composed of three color channels, a channel for the red color, a channel for the green color and a channel for the blue color. Each of the three color channels combined to produce those images was generated using a ratio between the brightness of the surface of the Orange Moon at two different wavelenghts (1.59/1.27 microns [red], 2.03/1.27 microns [green] and 1.27/1.08 microns [blue]). This technique known as the  band-ratio  technique allows us to lower the prominence of seams and to unveil subtle spectral variations on Titan's soil or landscape. The brown or dark areas found at low or mid-latitudes are dominated by dune fields. The bright, bluish or purplish areas may have a different composition and may be rich in water ice. The global views of Saturn's largest moon reveal that Titan is far from being uniform and that there is a significant contrast between bright areas and dark areas. The pools of surface liquids turn out to be mostly found in the polar areas of Titan. The VIMS instrument has been very useful in our understanding of Titan's surface and meteorology. The view in the lower part of the table shows the six global mosaics of Titan as well as a natural color view of its disk which clearly shows the opaque atmosphere.

Image Credit: NASA/JPL-Caltech/University of Nantes/University of Arizona.

 

The mosaic above represents a map of the giant moon of Saturn Titan. The global map of the Opaque Moon, generated in June 2015, is based on data acquired with the Imaging Science Subsystem (ISS) of the Cassini spacecraft during the  T100  Flyby performed on April 7, 2014. The image corresponds to an equidistant projection of the globe of the Orange Moon. The eye of the Cassini orbiter can see through the hazy atmosphere of Titan in the infrared or near-infrared spectrum. The well-known contrast between relatively low-albedo areas and relatively high-albedo areas can be clearly noticed in this map. The dark and relatively uniform areas found in the polar regions correspond to pools of liquids which are mainly composed of hydrocarbons like methane or ethane.

Source of the image: USGS/Astrogeology Science Center.

 

The image in the upper part of this table shows a portion of the Opaque Moon Titan and unveils an area of clouds. The view, whose file name is N00006521.jpg, was obtained on July 2, 2004 from the Cassini spacecraft with the CL1 and CB3 filters. The black-and-white view which represents a raw image had not been validated or calibrated. A validated/calibrated view had to be archived with the Planetary Data System proposed by NASA. Dynamic clouds have been clearly seen in the region of Ontario Lacus during the Summer season in the southern hemisphere of Saturn's largest moon. The view in the lower part of the table represents a colorized version of the original image. The color incorporated into the raw image is artificial.

Image credit for the original image: NASA/JPL-Caltech/Space Science Institute.
Image credit for the incorporation of the artificial color into the original view: Marc Lafferre, 2018.

 

The image above corresponds to a mosaic of the Opaque Moon Titan with a portion of the Gas Giant Saturn and its rings beyond the giant moon. The mosaic is based on four images acquired with the Narrow-Angle Camera of the Cassini spacecraft, on May 6, 2012, at a distance of about 478,000 miles or 770,000 kilometers from the Orange Moon. Surface features on Saturn's largest moon can be discerned in infrared or near-infrared views. One can notice in particular the remarkable contrast between a relatively low-albedo area and a relatively bright area.
The dark areas found at low latitudes or mid-latitudes are dominated by Seif dunes extending over long distances and shaped by the action of prevailing winds. One can clearly observe, here, the relatively bright area of Adiri and the relatively dark area of Shangri-La where the Huygens probe had landed on January 14, 2005. The landing site can be found at a low latitude in the lower-left part of the disk, quite close to the center of the disk, near the bright patch known as Adiri.
One can also discern some features of Titan's complex atmosphere rich in organics. A detached haze layer appears in the upper atmosphere of the giant moon which is bigger than Pluto or Mercury. The detached haze layer seems to be more complex above the polar areas since it appears darker above the polar areas. Ultraviolet light from the Sun plays a key role in the formation of Titan's haze containing various molecules such as methane, ethane, acetylene or hydrogen cyanide.
A sharp contrast between the appearance of Titan and the appearance of Saturn, dominated by hydrogen and helium, can be observed as well. The observation campaign of Titan via the Cassini orbiter, which had entered the system of Saturn in mid-2004, ended in 2017. A crash between the Cassini probe and Saturn had been planned for September 15, 2017.

Image Credit: NASA/JPL-Caltech/Space Science Institute.

 

The mosaic appearing in the upper part of this table reveals Saturn's largest moon Titan in different wavelengths of radiation. The three views of Titan were generated on the basis of data obtained on April 16, 2005 with the Wide Angle Camera of the Cassini probe. The images were acquired at distances ranging from about 173,000 kilometers to 168,200 kilometers or 107,500 miles to 104,500 miles from the Opaque Moon and from a Sun-Titan-probe, or phase, angle of 56 degrees. North appears in the upper part of each disk and is inclined 30 degrees to the right.
One can clearly notice that the use of different filters sensitive to visible light or infrared light can allow us to discern atmospheric features, haze layers, clouds or surface features. The cameras of the Cassini orbiter have several filters to study the atmosphere or the surface of the giant moon. The image found in the left part of the mosaic represents a natural color view combining photographs captured through three filters sensitive to red, green and violet radiation. The colors are close to the colors that our eyes would see. The Opaque Moon represents a hazy orange globe covered by a tenuous, bluish haze found in the upper atmosphere. Titan appears orange due to the haze of its atmosphere. The atmosphere of Saturn's largest moon is mainly composed of molecular nitrogen and the haze is rich in hydrocarbons.
At the time of the encounters of Titan performed by Voyager 1 and Voyager 2 in 1980 and 1981, planetologists had been frustrated by the fact that Titan's surface was completely hidden by the smog in the visible spectrum. Fortunately, the Cassini spacecraft was able to see through the haze and to identify surface features thanks to its filters sensitive to infrared wavelengths. The second view from the left in the mosaic reveals surface features and brightness variations on Titan at 938 nanometers. That wavelength which represents a near-infrared wavelength allows us to see through the smoggy atmosphere and to discern surface features. The image was generated by combining three different views acquired with the same filter, in order to improve the visibility of features on the ground. One can notice, in particular, a sharp contrast in the albedo or in the level of reflectivity between a relatively bright area and a relatively dark area. The bright areas are probably rich in water ice and the dark areas are probably rich in organics or hydrocarbons.
The view of Titan found in the right part of the mosaic represents a false-color composite composed of images acquired at different wavelengths. Two infrared views obtained at 938 and 889 nanometers and a visible light view acquired at 420 nanometers were mobilized to produce the final disk. Green corresponds to regions where the Cassini probe is able to discern surface features. Red corresponds to regions high in Titan's stratosphere where atmospheric methane is absorbing solar radiations. Blue surrounding the atmosphere, in its upper limits, corresponds to visible violet wavelengths at which the upper atmosphere and detached layers of haze can be better discerned. Another false-color view revealing the opposite hemisphere of the Orange Moon was generated from images captured during the first close flyby of the Opaque Moon in October 2004. During that particular encounter, we had been in a position to identify clouds in the area of the south polar region of the giant moon. The area was experiencing the Summer season. The observations of April 16, 2005 don't show any clear sign of cloud activity. The original views of the globes unveiled in the mosaic are presented below the mosaic in this table.

Image Credit: NASA/JPL/Space Science Institute.

 

The image in the upper part of this table corresponds to a raw image of Titan obtained on September 12, 2017 from the Cassini spacecraft. The file name of the image is N00289201.jpg. The view which has not been validated or calibrated was acquired using the CL1 and CB3 filters. A validated/calibrated view will be archived with the Planetary Data System of NASA. Some surface features can be discerned in the black and white image. One can notice a portion of the famous land of lakes and seas found in the high latitudes of the northern hemisphere, currently experiencing the Summer season. The view found in the lower part of the table corresponds to a colorized image of the raw view presented here.

Credit for the raw image: NASA/JPL-Caltech/Space Science Institute.
Credit for the colorization of the raw image: Marc Lafferre, 2018.    

 

The image above reveals the second largest moon of Saturn Rhea moving in front of Titan, the largest moon of the Gas Giant. Rhea orbits closer to Saturn than Titan does. One can notice the sharp contrast in the appearance of both moons. Rhea unveils a multitude of craters and is devoid of any significant atmosphere whereas the Orange Moon is covered by a completely opaque atmosphere. The atmospheric pressure on the surface of Titan is higher than that of the Earth at sea level. The atmosphere of the Hazy Moon is mainly composed of nitrogen and it unveils a relatively significant concentration of methane.
The image represents a natural color view acquired in visible light from the Narrow-Angle Camera of the Cassini spacecraft on November 19, 2009. The photograph was obtained at a distance of about 713,300 miles or 1,148,000 kilometers from the icy moon Rhea. The crescent of Rhea and Titan brings clues upon the position of the Sun or the orientation of solar radiations in this image. The orbital inclination of Titan and Rhea is particularly low relative to the plane of Saturn's equator.

Image Credit: NASA/JPL-Caltech/Space Science Institute.

 

The view above reveals the disk of Saturn's largest moon Titan eclipsed by the Ringed Planet Saturn. The Opaque Moon is weakly illuminated here. The camera is orientated upward toward the south polar region of the Orange Moon. The south pole appears on the terminator roughly a quarter of the way inward from the right of the visible sphere. The illuminated area observed here is found on the Saturn-facing side of the giant moon. In the shadow of the Gas Giant, the southern hemisphere of the Hazy Moon is illuminated by two sources: solar radiations scattered through the rings of the Gas Giant and refracted solar radiations going through the edge of Saturn's deep gas blanket.
The view was acquired in visible light with the Wide-Angle Camera of the Cassini spacecraft on May 7, 2009 at a distance of about 667,000 kilometers or 414,000 miles from the Opaque Moon and at a Sun-Titan-probe, or phase, angle of 58 degrees. In the background, stars appear elongated due to the relatively long camera exposure time representing 560 seconds. A relatively long exposure time was needed to reveal the faint light reflected by the disk of Titan.

Image Credit: NASA/JPL/Space Science Institute.

 

The view above clearly shows a portion of Titan's upper atmosphere where several blue haze layers can be discerned. The atmosphere of Saturn's largest moon is completely opaque in the visible spectrum and appears globally orange or brown. The atmosphere of the giant moon is mainly composed of nitrogen like the atmosphere of the Earth. Oxygen is absent or quasi-absent in the atmosphere of the Hazy Moon. Titan's atmosphere unveils a relatively high concentration of methane. The haze of the icy moon results, in particular, from interactions between molecules, ions or elements present in the upper part of Titan's atmosphere and ultraviolet radiations from the Sun. Complex organics or hydrocarbons falling toward the surface can be engendered in that soup of compounds or in that smog.
The image corresponds to a natural color view obtained in visible radiations from the Wide-Angle Camera of the Cassini probe on March 31, 2005. The view was acquired at a distance of about 20,556 miles or 33,083 kilometers from the Opaque Moon. The camera was orientated toward the north polar region on the night side. The north polar region where most lakes and seas are found on Titan was experiencing the Winter season. Only a small portion of Titan's illuminated crescent can be noticed on the right part of the image. The mission of the Cassini orbiter came to an end on September 15, 2017.

Image Credit: NASA/JPL-Caltech/Space Science Institute.  

 

Titan Images 2017
Titan Images 2016
Titan Images 2015
Titan Images 2014
Titan Images 2013
Titan Images 2012

Titan Images 2011
Titan Images 2010
Titan Images 2009
Titan Images 2008
Titan Images 2007
Titan Images 2006
Titan Images 2005, 2004

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