2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Pluto and Charon are at a distance of about 20 thousand kilometers from each other
Charon was able to protect Pluto's atmosphere from the effects of the solar wind. This could explain how a planetoid, probably almost devoid of a magnetic field, still manages to maintain its gas envelope, according to scientists at the Georgia Institute of Technology. The research is published in the journal Icarus.
Traces of the existence of Pluto's atmosphere were discovered back in 1985, when astronomers observed the passage of a planetoid in front of a distant star. Subsequent studies with the New Horizons probe showed that Pluto's gas envelope is cold, layered, and contains volatiles such as nitrogen and methane. At the same time, theoretical calculations say that the planetoid does not have a strong magnetic field that would help protect its gas envelope from being blown away by the solar wind. Therefore, the researchers suggested that its large satellite, Charon, could play an important role in preserving Pluto's atmosphere. According to planetary scientists, it acts as a shield from the solar wind.
The authors of the new work built a computer model that shows how the presence of Charon affects the movement of the stream of particles coming from the Sun. The researchers found that the satellite can change the direction of the solar wind, preventing the collision of highly ionized particles with gas molecules in Pluto's atmosphere. This effect is most powerful when Charon is between the Sun and Pluto, and weakest when it is behind a dwarf planet.
The speed of the solar wind (from 0 to 400 kilometers per hour) in the case when (1) Pluto does not have a satellite; (3) Charon is behind; (4) Charon is between Pluto and the Sun, but it has no atmosphere; (5) Charon sits between Pluto and the Sun and has a temporary atmosphere.
The decisive role in this is played by the temporary atmosphere of Charon. It can form even in the absence of a strong magnetic field, when part of Pluto's shell of gas is captured by a satellite, or when cryovolcanoes erupt. When interacting with the solar wind, part of Charon's temporary atmosphere is ionized, giving rise to the ionosphere. This creates a much more serious obstacle to particles flying towards Pluto, since the ionosphere is larger than the surface of Charon, which increases the size of the "shield", and also has high electrical conductivity, which allows more efficient deflection of the flow of solar plasma.
The researchers suggest that thanks to the "shield" Pluto was able to retain a significant part of the volatile elements in its atmosphere. However, it still loses its gas envelope. According to scientists, knowing how fast the atmosphere is blown off a dwarf planet, you can understand what it was in the early stages of Pluto's existence. The authors of the work believe that this will help to better understand the features of the solar system during its formation.
A recent analysis of Pluto's atmosphere has shown that volcanic activity must exist on the dwarf planet, due to which its gas envelope is replenished with nitrogen. According to scientists, this also explains how Pluto still manages to maintain its atmosphere.