Astronomy Picture of the Day
November 1, 2014

Another Specular Reflection on Titan
Another Specular Reflection on Titan

Credits: NASA/JPL/Space Science Institute - Credits for the additional process. and color.: Dr Paolo C. Fienga/LXTT/IPF

This Absolute Natural Color image-mosaic obtained from several pictures taken by the NASA - Cassini Spacecraft on August, 21, 2014, shows us the Sun glinting off of Titan's North Polar Seas. While the NASA - Cassini Spacecraft had captured, but separately, different views of the Polar Seas and the Sun glinting off of them in the past, this is the first time that separete Sunglints have been seen together in the same view. The Sunglint, also called "Specular Reflection", is the bright area visible near the 11 o'clock position at the upper left (Sx) of the picture. This mirror-like reflection, also known as "Specular Point", is located in the Southern Portion of Titan's largest Sea, such as Kraken Mare, just to the North of an Islands' Archipelagus that separates two different portions of the Sea.


This particular Sunglint was so bright that it saturated the detector of Cassini's Visual and InfraRed Mapping Spectrometer (or "VIMS", for short) instrument, which captured the view. It is also the Sunglint seen with the highest observation elevation so far - consider that the Sun was a full 40° above the Horizon as seen from Kraken Mare at that time -, and therefore much higher than the 22° of elevation that we have seen in yesterday's APOD. Because it was so bright, this Sunglint was visible through the Haze at much lower Wavelengths than before.


The Southern Portion of Kraken Mare (the area surrounding the Specular Feature toward upper left) displays a so-called "bathtub ring", such as a "Bright Margin of Evaporate Deposits", which indicates that the Sea was larger at some point in the past and has - in time - become smaller, probably because of evaporation. The Deposits are made of Material left behind after the liquid Methane & Ethane evaporatated.


The Hghest Resolution data from this Fly-By cover the labyrinth of Channels that connect Kraken Mare to another large Titanian Sea: Ligeia Mare. Furthermore, Ligeia Mare itself is partially covered in its Northern Reaches by a bright, arrow-shaped complex of Clouds. which are made of Liquid Methane Droplets, and could be actively refilling the Lakes and Seas of Titan with frequent Rainfalls.


This frame (which is a crop taken from an Original NASA - CASSINI Spacecraft's False Colors and NON Map-Projected image-mosaic published on the NASA - Planetary Photojournal with the ID n. PIA 18432) has been additionally processed, contrast enhanced, magnified to aid the visibility of the details, Gamma corrected and then re-colorized - according to an educated guess (or, if you wish, an informed speculation) carried out by Dr Paolo C. Fienga - in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Cassini Spacecraft and then looked outside, towards the Saturnian moon "Titan"), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among other things, the existence of different Elements (Gases) present in the Atmosphere of Titan, each having a different Albedo (---> Reflectivity) and Chemical Composition.


Note: it is possible (but we, as IPF, have no way to be one-hundred-percent sure of such a circumstance), that the actual luminosity of Titan - as it is in this frame - would appear, to an average human eye, a little bit lower than it has been shown (or, better yet: interpreted) here.



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