All news

Experts: Sun's weak activity allows to preserve nitrogen atmosphere of Saturn's moon

The nature of the origin and evolution of Titan's nitrogen atmosphere, which is thicker than the Earth's atmosphere, remains the topic of scientific discussions

KRASNOYARSK, November 20. /TASS/. The nitrogen atmosphere of Titan, the biggest moon of Saturn, has survived to this day due to the weak activity of the Sun. Such conclusions were reached by an international group of researchers, which included scientists at Siberian Federal University, the press service of the university told TASS.

The nature of the origin and evolution of Titan's nitrogen atmosphere, which is thicker than the Earth's atmosphere, remains the topic of scientific discussions. Scientists believe that these processes are strongly influenced by hard ultraviolet radiation coming from the Sun. However, until now they did not know exactly how intense this radiation was at the very beginning of the evolution of the atmosphere of the satellite planet of Saturn. Participants of the research using mathematical modeling were able to find the answer to this question. For the first time, the authors used a mathematical model of Titan's upper atmosphere for three possible evolutionary paths of the young Sun, characterized by low, moderate and high star activity. 

"Scientists have determined the loss of atmospheric gas throughout the history of Titan. The created mathematical model showed a very low rate of atmospheric loss today, very high though — in the early period of the history of the solar system. The most intense reduction in the nitrogen atmosphere took place at the earliest stage, when the hard ultraviolet radiation of the Sun was hundreds of times higher than modern radiation, which greatly accelerated the movement of streams of atmospheric particles", SFU press service told TASS.

In their calculations, the scientists proceeded from the fact that Titan acquired an atmosphere immediately after the formation of the planet. The researchers concluded that depending on the behavior of solar activity, the process of contraction of Titan's atmosphere could be high in the period from 100 to 1,000 million years after the formation of the solar system. Calculations have shown that only in the case of the scenario of a weak Sun activity in the past, the atmosphere had a chance to survive until the present time. 

"Since Titan now has a reliably dense atmosphere, the authors concluded that the young Sun evolved according to a scenario of weak activity. The performed studies also clarify the question of the origin of Titan's atmospheric nitrogen. They support the hypothesis of the origin of Titan's nitrogen, mainly from ammonia ice in the process of its decomposition ", the press service of Siberian Federal University quoted one of the authors of the study, Professor of the Department of Applied Mechanics of Siberian Federal University, Chief Researcher at the Institute of Computational Modeling (Russian Academy of Sciences) Nikolai Yerkaev.

Experts from US and Austria also participated in the study. The results of the scientific work are published in Monthly Notices of the Royal Astronomical Society (MNRAS).