Pluto can no longer be classified as a planet, but he is still fascinated. For example, how did the dwarf planet form and why is it so different from the planets? By investigating their chemical composition, researchers have developed a new idea: Pluto consists of comets.
According to the currently accepted model, planets are formed by the gradual growth of smaller objects – and Pluto, which is adjacent to the asteroid field of the Kuiper Belt, has long been considered to be similar. So this part is nothing new.
But there are similarities between Pluto and Comet 67P / Churyumov-Gerasimenko, of which scientists at the Southwest Research Institute (SwRI) assume they are not accidental. In particular, the nitrogen-rich ice in Pluto's Sputnik-Planitia
Thanks to the Pluto probe New Horizons and Rosetta, the 67P comet probe, we have a new and unprecedented wealth of data on Pluto and comets.
"We have developed the cosmochemical model of the Pluto Formation, which we refer to as" the giant comet, "said geochemist Christopher Glein of the Space Science and Engineering Division of SWRI.
"We have found an interesting correspondence between the estimated amount of nitrogen within the glacier and the amount that would be expected if Pluto were agglomerated by the agglomeration of about one billion comets or other objects of the Kuiper Belt of similar chemical composition as 67P Comet formed by Rosetta would be formed. "
Nitrogen on Pluto is related to methane on Titan or water on Earth ̵
The Earth's atmosphere is 78 percent nitrogen (our temperatures are not as cold as Pluto, so it remains gaseous), but Pluto's is about 98 percent. Between the nitrogen ice and the nitrogen atmosphere, the dwarf planet has an unusually high proportion.
Previously, scientists thought that nitrogen might come from comets that landed on Pluto – but this model would not explain the sheer volume
In addition to the comet model, the researchers also investigated a model in which Pluto made use of very cold ice with similar chemical compositions as the sun was formed. By examining these models, they hoped to better understand Pluto's leaky atmosphere to find out how much nitrogen escapes into the nearby space.
They also had to balance the amount of carbon monoxide in Pluto's atmosphere, and none of the models could explain how little it was.
"Our research suggests that Pluto's chemical composition derived from cometary building blocks is chemically modified by liquid water, perhaps even in an underground ocean," said Glein.
It is also possible that under the comet model, the missing carbon monoxide is trapped beneath Pluto's surface. Because there are more explanations for the lack of carbon monoxide in the comet model, it seems more likely than the solar model, the researchers said.
This is of course hypothetical and leads, as the researchers say, to "an appreciation of many subsequent questions that need to be addressed in future analyzes", eg. For example, whether the amount of nitrogen on comet 67P is representative of other comets and what role liquid water played in the development of volatiles on Pluto.
"This research builds on the fantastic successes of the New Horizons and Rosetta missions to broaden our understanding of the origins and evolution of Pluto," said Glein.
"Using Chemistry as a Tool for Detectives, we Can Track Certain Features Today, looking at Pluto's formation processes from a long time ago, this leads to a new appreciation of the wealth of Pluto's" life story "that we are only now gaining begin recording. "
The paper was accepted for publication in the journal Icarus and can be found on arXiv.
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