Canyon Itaka [1] ( lat. Ithaca Chasma ) - the largest canyon on the satellite of Saturn, Tethys . It stretches for a length of 2000 kilometers (3/4 of the circle of Tefii); its depth ranges from 3 to 5 kilometers, and its width reaches 100 kilometers. The edge is raised in places to a height of 0.5 km. Inside the canyon there are many long parallel depressions and ridges [2] [3] . In the southern part it is divided into two branches.
Ithaca Canyon was opened in 1980 on the pictures of Voyager 1 [3] . Named after the island of Ithaca - according to legend, the birthplace of Odysseus . This name was approved by the International Astronomical Union in 1982 [4] .
Content
Origin
The age of the canyon is estimated at 4.0 or 0.4-3.3 billion years, depending on the accepted value of the rate of accumulation of craters [5] . Now most astronomers are of the opinion that the Ithaca Canyon appeared during the freezing of the underground ocean of Tefii. The expansion of the bowels of the satellite led to the formation of a giant crack on the surface [2] . Craters that appeared before the solidification of the liquid layers of Tefii most likely wiped away under the influence of geological activity.
The underground ocean of Tefii, which may have existed in the early stages of its history, did not previously freeze due to the significant elongation of its orbit. This elongation led to a change in the magnitude of tidal forces at each revolution. As a result, the bowels of the satellite were regularly deformed, which was accompanied by friction and heating. The reason for the elongation of the orbit of Tefii was its orbital resonance with Dion . Later, Tefia came out of resonance, its orbit was rounded and the heating of the bowels ceased. Frozen water tore the surface, resulting in the emergence of Ithaca Canyon.
There is another hypothesis of the origin of this canyon. Near the center of one of the hemispheres into which he shares Tethys, lies a large impact crater Odysseus . Such an arrangement of these objects indicates their possible connection. According to one assumption, the canyon created seismic waves from the impact that formed this crater [2] . Against this version, it is said that the concentration of craters inside the Odyssey crater is less than in the Ithac canyon, and this means that their age is different [5] .
See also
- List of relief details in Tefii
Notes
- ↑ Burba G.A. Nomenclature of the relief details of Saturn's satellites / Otv. ed. K.P. Florensky and Yu. I. Efremov. - Moscow: Nauka, 1986. - S. 50–54. - 80 p.
- ↑ 1 2 3 Moore, JM; Schenk, Paul M .; Bruesch, Lindsey S. et al. Large impact features on middle-sized icy satellites (English) // Icarus : journal. - Elsevier , 2004 .-- Vol. 171 , no. 2 . - P. 421-443 . - DOI : 10.1016 / j.icarus.2004.05.05.009 . - .
- ↑ 1 2 Smith BA A new look at the Saturn system - The Voyager 2 images // Science: journal. - 1982. - Vol. 215 , no. 4532 . - P. 504-537 . - DOI : 10.1126 / science.215.4532.504 . - . - PMID 17771273 .
- ↑ Ithaca Chasma . Gazetteer of Planetary Nomenclature . International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN) (June 5, 2008). Date of treatment March 25, 2013. Archived on April 5, 2013.
- ↑ 1 2 Giese, Bernd; Wagner, Roland; Neukum, Gerhard et al. Tethys: Lithospheric thickness and heat flux from flexurally supported topography at Ithaca Chasma (Eng.) // Geophysical Research Letters : journal. - 2007 .-- November ( vol. 34 , no. 21, L21203 ). - DOI : 10.1029 / 2007GL031467 . - .