As shown by a new simulation of the upper atmosphere of Pluto, it goes so far from the planet that some stray molecules can fly even to Charon. The thickness of the atmosphere dwarf planet estimated at approximately 10 390 km, that is about 4.5 diameter of Pluto, which covers the distance to Charon more than half.

A year ago, there was proposed a new model for estimating the size of the upper atmosphere during the solar minimum. Justin Erwin from the University of Virginia (USA) and his colleagues have expanded it to include solar maximum and average solar heating. This led to an unexpected result. The rate at which molecules escape from Pluto, was hardly less, and it gave a completely different picture of the atmosphere.

The surface of Pluto in the view of the artist (ESO image / L. Cal?ada).

The atmosphere of Pluto consists mainly of methane, nitrogen and carbon monoxide, the source of which, apparently, is ice on the surface of the planet. The size of the atmosphere undergoes changes depending on the position of Pluto relative to the Sun (remember, this object has an elliptical orbit): when he walks closer, ice evaporates and gases slowly go into space. Then the ice accumulates again. Year on Pluto continues to 248 earth years, and the last time in the nearest to the Sun point of the planet appeared in 1989.

Difficulties related to the study of the atmosphere of Pluto, partly caused by the debate about how it should be measured. The closer to the planet, the more is absorbed ultraviolet radiation from the Sun, and remains one of only infrared heating. The further - the thinner atmosphere, and ultraviolet actively affects molecules. That is why for different layers use different models.

Do not forget that the size of Pluto still remains unknown (so far away from us this object). In this case, scientists assumed that its diameter is 2 300 km

Now, Pluto is paid particularly close attention, because in 2015 there should arrive the spacecraft "New horizons" and need to know in advance what dangers lie in wait traveler and what observations should be performed first.

The study is published on the website arXiv and, probably, will appear in the journal Icarus.

Based on the materials Space.Com.