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takyon [soylentnews.org] writes:

Pluto May Not Be a Planet, But It Could Be Made Out of Millions of Comets [sciencealert.com]

Pluto may not be categorised as a planet any more, but it still holds plenty of fascination. For instance, how did the dwarf planet form, and why is it so different from the planets? By examining its chemical composition, researchers have come up with a new idea: Pluto is made of comets.

According to the currently accepted model, planets are formed by the gradual accretion of smaller objects - and Pluto, situated right next to the Kuiper Belt asteroid field, has long been thought to have formed the same way. So that part is nothing new.

But there are similarities between Pluto and Comet 67P/Churyumov-Gerasimenko that scientists from the Southwest Research Institute (SwRI) believe may not be coincidental. In particular, the nitrogen-rich ice in Pluto's Sputnik Planitia [wikipedia.org].

[...] "We found an intriguing consistency between the estimated amount of nitrogen inside the glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P, the comet explored by Rosetta."

Also at SwRI [swri.org].

Primordial N₂ provides a cosmochemical explanation for the existence of Sputnik Planitia, Pluto (DOI unknown, Journal Icarus) (arXiv [arxiv.org])

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