Titanís atmosphere. (Image from the Cassini orbiter)
The article in the journal Icarus compares the chemical composition of Titanís atmosphere with parameters predicted by a mathematical model. The atmosphere of Saturnís largest moon was described by a model that took into account the presence of 83 neutral molecules and33 ions and420 different chemical reactions between them. Despite the fact that Titan is located much further from the Sun than the Earth and that radiation flux coming from the Sun to the moon is 100 times less, the intensity of UV rays is enough to spur photochemical reactions in the upper layers of Titanís atmosphere.
The data regarding the composition of Titanís atmosphere, which is 1.6 times denser near the surface than the Earthís air, was obtained from several sources, the main of which was the Cassini orbiter. It was equipped with a number of gauges, including ultraviolet and infrared spectrometers and equipment for studying the ions that were drawn into space. Within ten years in Saturnís orbit, a plasma complex and a mass spectrometer designed specifically for this research project gathered enough data to compare it with mathematical models.
In addition to Cassini, part of the data was obtained using the IRAM ground submillimeter telescope and the Hershel infrared space observatory. Data onthe distribution of aerosol particles in Titanís atmosphere was received from a unique space capsule, Huygens, which landed on Titan for the first time in the history of mankind and sent the first photos of its surface.
Comparing this data with the previously developed model, Krasnopolsky showed that the theoretical description of Titanís atmosphere matches the reality quite accurately. There are discrepancies, however, but they are caused by inevitable measurement errors Ė so far the concentrations of many substances are approximate. The most important thing is not the absolute matching of specific parameters but the correctness of the general model of chemical processes.
ďThe coherence of the model with reality means that we can correctly tell where different substances go from Titanís ionosphere and where they come from,Ē Krasnopolsky said.
Krasnopolsky is considered a leading global expert on the atmosphere of celestial bodies of the solar system. He has participated in the creation of spectrometers for a variety of spacecraft, including the legendary Voyagers and the first Soviet interplanetary probes.
Source: Moscow Institute of Physics and Technology