Abnormally bright spots detected in the Equatorial regions of Titan about 20 years ago, can be dried up lakes, is reported in Nature Communications. This is the conclusion of astronomers came by looking at the information collected by the probe “Cassini” and the two observatories.
Titan is the only celestial body in the Solar system, where there are hydrological cycles, similar to the tropospheric water cycle on Earth. On the moon’s surface is lakes, rivers and even the sea — though they consist mainly of methane and ethane. About 20 years ago the instruments of the Observatory, the Arecibo telescope and the Green Bank Telescope discovered an unusual radar reflection in the tropical region of Titan, which astronomers have interpreted as evidence of the presence of the liquid. However, subsequent observations made by the probe “Cassini” found no bodies of water near the equator and showed that the lakes on a celestial body usually concentrated in the polar regions.
Jason Hopfgartner (Jason Hofgartner D.) from the California Institute of technology and his colleagues have compiled the available images and spectra received by the probe “Cassini” and two observatories, and re-examined them. The analysis showed that the bright spots on Titan’s surface can be either dunes or remaining after the rain, puddles or dried up lakes. However, the rains on Saturn are quite rare, Cassini had seen them only twice, in 2004 and 2010, so the appearance of large lakes due to precipitation, scientists considered it unlikely, and dunes are formed, as a rule, in other regions of Titan, so the scientists cut off and this hypothesis.
According to the authors, the anomalous radar reflections was created by dried-up lakes. Spectroscopic, morphological and topographic evidence indicates their similarity to paleoselli or paleobotany in the polar regions of Titan. They are not as mirror as liquid water, however, areas where the spots are different from other areas in the tropical region of Titan smoothness and dielectric constant (the composition). The question of what happened to the lakes and why they vanished remains a mystery. The researchers suggest that it could be moved to other parts of the satellite, or to evaporate under the sunlight.
Last November, astronomers made the first geomorphological map of Titan, which helped to explain what is happening on the satellite processes. In 2026 to the celestial body will go oktokopter Dragonfly, which will be engaged in more detailed study of the surface and atmosphere of a celestial body.