it is a bit particular for me to post here and submit pictures or subjects to APOD ! I was watching for them since such a long time now with great pleasure and interest, with maybe one day the hope to be part of it ! Your website is a wonderful way to all share our passion, being a professional astronomer or not !
We recently - the 4 june in fact - publish with colleagues a study on Titan's clouds and climate in the journal Nature and I wonder if you would be interested in putting one of our pictures for an incoming APOD.
Our paper compiles 3.5 years of continuous Titan's clouds monitoring with the infrared mapping spectrometer (VIMS - for Visual and Infrared Mapping Spectrometer) onboard Cassini. This allowed us to constrain with a good accuracy and a sufficiently good time and space coverages the meteorology of Titan, by comparing our observations with a climate model for Titan. One of our conclusions is that Titan is surely experiencing at the present time a warmer and wetter late summer (in the south hemisphere) than predicted by the models. This is a way to refine climate models and to better understand Titan's exotic climatology (the evolution of the meteorology with seasons) and hydrocarbon cycles. Of course, with the aim to better comprehend how do work all the planetary atmospheres of our solar system.
I can propose to you some pictures which illustrate our study (some maybe a bit technical, others being just nice, at least to me!):
These are the maps of Titan’s clouds derived from VIMS (Visual and Infrared Mapping Spectrometer) observations from July 2004 to December 2007. Our detections are presented in cylindrical (top) and polar orthographic (bottom) projections. The colours of the clouds correspond to the date of each cloud observation. A VIMS greyscale mosaic of Titan’s surface is used as background. Clouds are found to be distributed in three clustered regions: the two poles and the southern temperate latitudes. Only very few occurrences of clouds are found in equatorial regions. Credits: Nature publishing group - NASA/JPL/University of Arizona/University of Nantes - S. Rodriguez.
Left: Titan's surface view, annotated with some official regions names. Credits: NASA/JPL/Space Science Institute. Right: Same hemisphere, showing the map of clouds detected between July 2004 and December 2007 with NASA’s Cassini spacecraft visual and infrared mapping spectrometer, and reprojected on Titan's globe. Credits: NASA/JPL/University of Arizona/University of Nantes - S. Rodriguez.
RGB false-color images make up this mosaic and show the clouds at 40 to 50 degrees mid-latitude. The images were taken by NASA’s Cassini spacecraft visual and infrared mapping spectrometer during a close flyby of Titan on Sept. 7, 2006, known as T17. Each image is a color composite with red shown at the 2-micron wavelength, green at 1.6 microns and blue at 2.8 microns. An infrared color mosaic is also used as a background (red at 5 microns, green at 2 microns and blue at 1.3 microns). The characteristic elongated mid-latitude clouds, which are easily visible in bright bluish tones (see close-up in the inset) are still active even late into 2006-2007. According to climate models these clouds should have faded out since 2005. Scientists will continue to observe the long-term changes during Cassini’s extended mission, which runs until the fall of 2010. Credits: NASA/JPL/University of Arizona/University of Nantes - S. Rodriguez.
This infrared image of Saturn’s moon Titan shows a large burst of clouds at in the moon’s south polar region. This image is a color composite, with red shown at a 5-micron wavelength, green at 2.7 microns, and blue at 2 microns. An infrared color mosaic is also used as a background image (red at 5 microns, green at 2 microns, blue at 1.3 microns). The images were taken by Cassini’s visual and infrared mapping spectrometer during a flyby of Titan on March 26, 2007, known as T27. Titan’s south polesouthern hemisphere still shows a very active meteorology (the cloud appears in white-reddish tones) even in 2007. According to climate models, these clouds should have faded out since 2005. Scientists will continue to observe the long-term changes during Cassini’s extended mission, which runs until the fall of 2010. Credits: NASA/JPL/University of Arizona/University of Nantes - S. Rodriguez.
You can find official NASA press releases here:
http://saturn.jpl.nasa.gov/news/newsrel ... e20090603/
http://www.nasa.gov/mission_pages/cassi ... 12005.html
http://www.nasa.gov/mission_pages/cassi ... 12004.html
and in french, along with a video (in english), here:
http://irfu.cea.fr/Sap/Phocea/Vie_des_l ... d_ast=2611
If you are interested in preparing an APOD with this material and want to have further information, please don't hesitate to contact me.
Thank for your consideration,
Sebastien Rodriguez, Paris.
