Fensal Is Equatorial Dark Albedo Feature on Titan's Saturn-Facing Side

Summary: Fensal is an equatorial dark albedo feature on Titan's Saturn-facing side that forms a low albedo quartet with Aztlan, Aaru and Senkyo.

composite image, at near-infrared wavelengths, of Titan's mostly Saturn-facing hemisphere shows parallel dark albedo features of Fensal (top) and Aztlan (below) as sidewise letter H; images obtained during T-114 flyby, Nov. 13, 2015, by Cassini spacecraft's Visible and Infrared Mapping Spectrometer (VIMS), at a closest-approach altitude of 6,200 miles (10,000 kilometers); blue for 1.3 micron-centered wavelengths, green for 2.0 micron-centered wavelengths, red for 5.0 micron-centered wavelengths; image addition date 2015-12-04; image credit NASA/JPL/University of Arizona/University of Idaho: No copyright restrictions, via NASA Image and Video Library

Fensal is an equatorial dark albedo feature on Titan's Saturn-facing side that forms an equatorial quartet of low albedo, or low reflectance, with the three optically dark neighboring regions of Aztlan, Aaru and Senkyo.

Fensal is centered at 5 degrees north latitude, 30 degrees west longitude, according to the International Astronomical Union’s (IAU) Gazetteer of Planetary Nomenclature. The Gazetteer gives the low albedo feature's center latitude of 5 degrees north as its northernmost and southernmost latitudes and its center longitude of 30 degrees west as its easternmost and westernmost longitudes.

Fensal finds a trio of dark albedo neighbors in Titan's equatorial belt. Fensal forms a quartet of low reflectance with northern equatorial-centered Aaru and with southern equatorial-centered Aztlan and Senkyo.

Aztlan's center lies to the south of Fensal. Aztlan is centered at minus 10 degrees south latitude, 20 degrees west longitude. The center coordinates of minus 20 degrees south and 20 degrees west longitude are given as the low reflector's northernmost-southernmost latitudes and easternmost-westernmost longitudes, respectively.

Aaru and Senkyo complete the Saturn-facing side's dark quartet. Aaru and its southern neighbor, Senkyo, lie to the east of the Fensal-Aztlan duo.

Aaru is centered at 10 degrees north latitude, 340 degrees west longitude. Its center latitude and longitude are repeated as the dark albedo feature's northernmost-southernmost latitudes and easternmost-westernmost longitudes.

Senkyo is centered at minus 5 degrees south latitude, 320 degrees west longitude. Its center coordinates are also given as Sankyo's northernmost-southernmost latitudes and easternmost-westernmost longitudes.

Prior to official naming, the Fensal-Aztlan neighborhood was known as "the H," for the appearance of a sidewise h formed by the two dark albedo features, according to NASA Jet Propulsion Laboratory's (JPL) Photojournal website's post, "Monitoring 'Fensal-Aztlan,'" published Sep. 13, 2005. Fensal and Aztlan represent the sidewise letter's northern and southern sides, respectively.

A plethora of small landforms distinguish Fensal. The September 2005 post describes the landforms as small "islands" that are currently interpreted as water ice upland areas. Lower terrain, infilled with dark particles precipitated from the atmosphere, surround the insular landforms. The roughly circular landforms have diameters ranging from 5 to 40 kilometers (3 to 25 miles). Although Fensal's islands generally appear as scatterings rather than as clusters, some present an east-west orientation to their long axis.

Fensal offers a few exceptions, such as Bazaruto Facula, to the dark albedo feature's typically small insular landforms. The bright spot (Latin: facula, "little torch") is centered at 11.6 degrees north latitude, 16.1 degrees west longitude. Its northernmost and southernmost latitudes reach 13.7 degrees north and 8.4 degrees north, respectively. Its easternmost and westernmost longitudes extend to 14.3 degrees west and 18.6 degrees west, respectively. Bazaruto Facula spans 215 kilometers.

Titan's longitudinal dunes are confined to the moon's equatorial belt. Dune size and pattern, however, varies with altitude and latitude, according to the Photojournal post, "Dune Patterns," published Jan. 23, 2012. Fensal's elevated location accounts for the dark albedo feature's thin, widely separated dune fields. Also, thin coverings of sand characterize the gaps between Fensal's dune fields.

Fensal joins Belet and Shangri-La as Titan's three largest sand seas, according to planetary geophysicist Antoine Lucas and seven co-authors in their article, "Texture and Composition of Titan's Equatorial Sand Seas Inferred From Cassini SAR Data," published in the October 2019 issue of Journal of Geophysical Research JGR: Planets. Fensal claims the highest altitude and latitude of the three sand seas. Belet is centered at minus 5 degrees south latitude, 255 degrees west longitude. Shangri-La is centered at minus 10 degrees south latitude, 165 degrees west longitude.

The International Astronomical Union approved Fensal's name in 2006. Titan's albedo features are named for "Sacred or enchanted places, paradise, or celestial realms from legends, myths, stories, and poems of cultures from around the world," according to IAU convention. The Gazetteer of Planetary Nomenclature's entry for Fensal attributes the dark albedo feature's origin to Norse mythological goddess of marriage Frigga's mansion. Fensal (Femsalir) welcomed married couples who had lived virtuously on Earth.

mosaic created from images acquired, during flyby Sept. 7, 2005, by Cassini spacecraft's Narrow-Angle Camera (NAC), with 938 nanometer-centered infrared light wavelength filter; images obtained from approximate distance ranges of 200,600 to 191,800 kilometers (124,600 to 119,200 miles) from Titan; mosaic centered on 7 degrees north latitude, 21 degrees west longitude; image credit NASA/JPL/Space Science Institute: No known copyright restrictions, via NASA Image and Video Library

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Dedication

This post is dedicated to the memory of our beloved blue-eyed brother, Charles, who guided the creation of the Met Opera and Astronomy posts on Earth and Space News. We memorialized our brother in "Our Beloved Blue-Eyed Brother, Charles, With Whom We Are Well Pleased," published on Earth and Space News on Thursday, Nov. 18, 2021, an anniversary of our beloved father's death.

Image credits:

composite image, at near-infrared wavelengths, of Titan's mostly Saturn-facing hemisphere shows parallel dark albedo features of Fensal (top) and Aztlan (below) as sidewise letter H; images obtained during T-114 flyby, Nov. 13, 2015, by Cassini spacecraft's Visible and Infrared Mapping Spectrometer (VIMS), at a closest-approach altitude of 6,200 miles (10,000 kilometers); blue for 1.3 micron-centered wavelengths, green for 2.0 micron-centered wavelengths, red for 5.0 micron-centered wavelengths; image addition date 2015-12-04; image credit NASA/JPL/University of Arizona/University of Idaho: No copyright restrictions, via NASA Image and Video Library @ https://images.nasa.gov/details-PIA20016; May be used for any purpose without prior permission, via NASA JPL Photojournal @ https://photojournal.jpl.nasa.gov/catalog/pia20016

mosaic created from images acquired, during flyby Sept. 7, 2005, by Cassini spacecraft's Narrow-Angle Camera (NAC), with 938 nanometer-centered infrared light wavelength filter; images obtained from approximate distance ranges of 200,600 to 191,800 kilometers (124,600 to 119,200 miles) from Titan; mosaic centered on 7 degrees north latitude, 21 degrees west longitude; image credit NASA/JPL/Space Science Institute: No known copyright restrictions, via NASA Image and Video Library @ https://images.nasa.gov/details-PIA07732; May be used for any purpose without prior permission, via NASA JPL Photojournal @ https://photojournal.jpl.nasa.gov/catalog/PIA07732

For further information:

Archinal, Brent A.; Michael F. A’Hearn; Edward Bowell; Al Conrad; Guy J. Consolmagno; Regis Courtin; Toshio Fukushima; Daniel Hestroffer; James L. Hilton; Georgij A. Krasinsky; Gregory Neumann; Jürgen Oberst; P. Kenneth Seidelmann; Philip Stooke; David J. Tholen; Peter C. Thomas; and Iwan P. Williams. "Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2009." Celestial Mechanics and Dynamical Astronomy, vol. 109, issue 2 (Dec. 4, 2010): 101-135.
Available via Astropedia @ https://astropedia.astrogeology.usgs.gov/download/Docs/WGCCRE/WGCCRE2009reprint.pdf
Available via Springer Link @ https://link.springer.com/article/10.1007/s10569-010-9320-4
Available via USGS Publications Warehouse @ https://pubs.er.usgs.gov/publication/70157540

Brossier, J. F. (Jeremy Florian): S. (Sébastien) Rodriguez; T. Cornet; A. Lucas; J. Radebaugh; L. (Luca) Maltagliati; S. (Stéphane) Le Mouélic; A. (Anezina) Solomonidou; A. (Athena) Coustenis; M. (Mathieu) Hirtzig; R. (Ralf) Jaumann; K. Stephan; and C. Sotin. "Geological Evolution of Titan's Equatorial Regions: Possible Nature and Origin of the Dune Material." Journal of Geophysical Research JGR Planets, vol. 123, issue 5 (May 2018): 1089-1112.
Available via Wiley Online @ https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2017JE005399
Available via Wiley Online @ https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2017JE005399

Brossier, Jeremy. "What Is Happening in Titan's Equatorial Belt?" Planetary Geomorphology Image of the Month, June 1, 2018.
Available @ https://planetarygeomorphology.wordpress.com/2018/06/01/what-is-happening-in-titans-equatorial-belt/

Cain, Fraser. "Fensal-Aztlan Region on Titan." Univere Today. Sep. 14, 2005.
Available @ https://www.universetoday.com/10931/fensal-aztlan-region-on-titan/

Daley, Jason. "First Global Map of Saturn’s Moon Titan Reveals Secrets of Earth’s ‘Deranged’ Twin." Smithsonian Magazine > SmartNews. Nov. 20, 2019.
Available @ https://www.smithsonianmag.com/smart-news/first-map-earths-deranged-twin-and-saturns-moon-titan-completed-180973607/

Florian Brossier, Jeremy; Sébastien Rodriguez; Luca Maltagliati; Stéphane Le Mouélic; Anezina Solomonidou; Athena Coustenis; Mathieu Hirtzig; Ralf Jaumann; and Robert H. Brown. "Equatorial Belt of Titan: Aaru Region as Seen by VIMS/Cassini." American Astronomical Society, 48th Division for Planetary Sciences (DPS) / 11th European Planetary Science Congress (EPSC) International Conference, Oct. 10-16, 2016, Pasadena, California.
Available via DLR (Deutsches Zentrum für Luft- und Raumfahrt) elib @ https://elib.dlr.de/105102/
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ https://ui.adsabs.harvard.edu/abs/2016DPS....4841206F/abstract

Greicius, Tony. "Dunelands of Titan." NASA > Image Feature > Jet Propulsion Laboratory. Nov. 2, 2015. Last updated Aug. 7, 2017.
Available @ https://www.nasa.gov/image-feature/jpl/pia18341/dunelands-of-titan

Huber, Lyle, cur. "Cassini RADAR Titan SAR Images." NASA PDS: The Planetary Atmosphere Node > Data and Services > Atmospheres Data.
Available @ https://atmos.nmsu.edu/data_and_services/atmospheres_data/Cassini/inst-radar-sar.html

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Categories (Themes) for Naming Features on Planets and Satellites.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Documentation > Surface Feature Categories.
Available @ https://planetarynames.wr.usgs.gov/Page/Categories

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Coordinate Systems for Planets and Satellites.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Documentation > Target Coordinate Systems.
Available @ https://planetarynames.wr.usgs.gov/TargetCoordinates

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Descriptor Terms (Feature Types).” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Documentation > Descriptor Terms.
Available @ https://planetarynames.wr.usgs.gov/DescriptorTerms

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Target: Titan.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Nomenclature > Saturn.
Available @ https://planetarynames.wr.usgs.gov/Page/TITAN/target

International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). “Aaru.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Oct. 1, 2006.
Available @ https://planetarynames.wr.usgs.gov/Feature/6981

International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). "Aztlan.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Oct. 1, 2006.
Available @ https://planetarynames.wr.usgs.gov/Feature/6983

International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). "Bazaruto Facula.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Oct. 1, 2006.
Available @ https://planetarynames.wr.usgs.gov/Feature/6992

International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). "Belet.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Oct. 1, 2006.
Available @ https://planetarynames.wr.usgs.gov/Feature/6984

International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). “Fensal.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Oct. 1, 2006.
Available @ https://planetarynames.wr.usgs.gov/Feature/7011

International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). “Senkyo.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Oct. 1, 2006.
Available @ https://planetarynames.wr.usgs.gov/Feature/6989

International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). “Shangri-La.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated April 20, 2009.
Available @ https://planetarynames.wr.usgs.gov/Feature/6990

Jet Propulsion Laboratory. "PIA02145: Mapping Titan's Changes." NASA JPL Photojournal. Image addition date 2006-02-10.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA02145

Jet Propulsion Laboratory. "PIA07730: Titan's Sideways Cipher." NASA JPL Photojournal. Image addition date 2005-08-25.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA07730

Jet Propulsion Laboratory. "PIA07732: Monitoring 'Fensal-Aztlan.'" NASA JPL Photojournal. Image addition date 2005-09-13.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA07732

Jet Propulsion Laboratory. "PIA07753: Naming New Lands -- September Flyby (annotated)." NASA JPL Photojournal. Image addition date 2005-11-04.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA07753

Jet Propulsion Laboratory. "PIA07755: Naming New Lands -- September Flyby." NASA JPL Photojournal. Image addition date 2005-11-04.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA07755

Jet Propulsion Laboratory. "PIA10575: A Titanic Mansion." NASA JPL Photojournal. Image addition date 2009-02-10.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA10575

Jet Propulsion Laboratory. "PIA11542: Enchanted Titan." NASA JPL Photojournal. Image addition date 2009-07-23.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA11542

Jet Propulsion Laboratory. "PIA11560: Low Albedo Foursome." NASA JPL Photojournal. Image addition date 2009-08-18.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA11560

Jet Propulsion Laboratory. "PIA12531: Dark Quartet." NASA JPL Photojournal. Image addition date 2010-01-20.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA12531

Jet Propulsion Laboratory. "PIA14663: Fenzal and Aztlan." NASA JPL Photojournal. Image addition date 2013-06-03.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA14663

Jet Propulsion Laboratory. "PIA15225: Dune Patterns." NASA JPL Photojournal. Image addition date 2012-01-23.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA15225

Jet Propulsion Laboratory. "PIA18341: Dunelands of Titan." NASA JPL Photojournal. Image addition date 2015-11-02.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA18341

Jet Propulsion Laboratory. "PIA20016: Peering Through Titan's Haze." NASA JPL Photojournal. Image addition date 2015-12-04.
Available @ https://photojournal.jpl.nasa.gov/catalog/pia20016

Le Gall, Alice; M.A. Janssen; L.C. Wye; A.G. Hayes; R.D. Lorenz; J. Radebaugh; B. Stiles; and Cassini RADAR Team. "Dunes on Titan: Comparison of the Fensal and Belet Dune Regions Using Multiple Datasets." American Astronomical Society, DPS meeting #42; Bulletin of the American Astronomical Society, vol. 42 (October 2010): 1076.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ https://ui.adsabs.harvard.edu/abs/2010DPS....42.5502L/abstract

Lucas, Antoine; Sébastien Rodriguez; Florentin Lemonnier; A. (Alice) Le Gall; Shannon McKenzie; C. Ferrari; Philippe Paillou; and Clement Narteau. "Texture and Composition of Titan's Equatorial Sand Seas Inferred From Cassini SAR Data: Implications for Aeolian Transport and Dune Morphodynamics." The Journal of Geophysical Research JGR: Planets (October 2019).
Available via ResearchGate GmbH @ https://www.researchgate.net/publication/313519792_Texture_and_composition_of_Titan%27s_equatorial_sand_seas_inferred_from_Cassini_SAR_data_Implications_for_aeolian_transport_and_dune_morphodynamics

Marriner, Derdriu. "Aaru Is Equatorial Dark Albedo Feature on Titan's Saturn-Facing Sidey." Earth and Space News. Wednesday, Jan. 19, 2022.
Available @ https://earth-and-space-news.blogspot.com/2022/01/aaru-is-equatorial-dark-albedo-feature.html

Marriner, Derdriu. "Adiri Is Equatorial Bright Albedo Feature on Titan's Anti-Saturn Side." Earth and Space News. Wednesday, Jan. 26, 2022.
Available @ https://earth-and-space-news.blogspot.com/2022/01/adiri-is-equatorial-bright-albedo.html

Marriner, Derdriu. "Aztlan Is Equatorial Dark Albedo Feature on Titan's Saturn-Facing Side." Earth and Space News. Wednesday, Feb. 2, 2022.
Available @ https://earth-and-space-news.blogspot.com/2022/02/aztlan-is-equatorial-dark-albedo.html

Marriner, Derdriu. "Belet Is Equatorial Dark Albedo Feature on Titan's Anti-Saturn Side." Earth and Space News. Wednesday, Feb. 9, 2022.
Available @ https://earth-and-space-news.blogspot.com/2022/02/belet-is-equatorial-dark-albedo-feature.html

Marriner, Derdriu. "Ching-Tu Is Equatorial Dark Albedo Feature on Titan's Anti-Saturn Side." Earth and Space News. Wednesday, Feb. 16, 2022.
Available @ https://earth-and-space-news.blogspot.com/2022/02/ching-tu-is-equatorial-dark-albedo.html

Marriner, Derdriu. "Christiaan Huygens Discovered Saturnian Satellite Titan March 25, 1655." Earth and Space News. Wednesday, March 21, 2012.
Available @ https://earth-and-space-news.blogspot.com/2012/03/christiaan-huygens-discovered-saturnian.html

Marriner, Derdriu. "Dilmun Is Equatorial Bright Albedo Feature on Titan's Anti-Saturn Side." Earth and Space News. Wednesday, Feb. 23, 2022.
Available @ https://earth-and-space-news.blogspot.com/2022/02/dilmun-is-equatorial-bright-albedo.html

Marriner, Derdriu. "Titan Has Eight Low Albedo Features That Darken Its Surface." Earth and Space News. Wednesday, Jan. 12, 2022.
Available @ https://earth-and-space-news.blogspot.com/2022/01/titan-has-eight-low-albedo-features.html

Marriner, Derdriu. "Titan Has Five High Albedo Features That Brighten Its Surface." Earth and Space News. Wednesday, Jan. 5, 2022.
Available @ https://earth-and-space-news.blogspot.com/2022/01/titan-has-five-high-albedo-features.html

Marriner, Derdriu. "Visible and Infrared Mapping Spectrometer VIMS Shows Titanean Surface." Earth and Space News. Wednesday, March 29, 2012.
Available @ https://earth-and-space-news.blogspot.com/2012/03/visible-and-infrared-mapping.html

Stiles, Bryan. Cassini Radar Basic Image Data Records SIS Version 1.4. D-27889. Pasadena CA: NASA Jet Propulsion Laboratory, California Institute of Technology, Sep. 27, 2005.
Available @ https://pds-imaging.jpl.nasa.gov/data/cassini/cassini_orbiter/CORADR_0051/DOCUMENT/BIDRSIS.HTML