Kuiper Belt Object Arrokoth Has More Similarities to a Snowman Aside From Their Shape

Kuiper Belt Object Arrokoth Has More Similarities to a Snowman Aside From Their Shape
(Photo: Wikimedia Commons/NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Roman Tkachenko.)

Arrokoth dubbed the "space snowman," shares many things with a snowman aside from its shape. Researchers believe ancient ice is locked within it.

Space Snowman Arrokoth Contains Ancient Ice

In a new study, the "space snowman," often referred to as "Ultima Thule," is viewed by the research team as a case study for further entities in the Kuiper Belt. This belt represents an ice ring of cometary objects found in the furthest parts of our solar system, outside of Neptune's orbit.

Since these bodies are made of material that was present when the planets formed 4.5 billion years ago, the Arrokoth result implies that their original ice content may still be present. Due to how quickly they may evaporate, these ices are sometimes known as "volatiles."

The team's idea may also clarify why some of these items behave like "ice bombs," exploding when they approach the sun, by reassessing the innards of Kuiper Belt objects.

According to the team's model, Arrokoth is made of water, ice, and carbon monoxide. The comet loses gas and ice through sublimation when its surface heats up as it travels by the sun. Sublimation is the process of a solid turning straight from a liquid phase into a gas.

Over time, the sublimation front would descend through carbon monoxide ice stored and trapped inside a water ice matrix. The locked-up carbon monoxide ice starts to sublimate as well, but instead of escaping, the ice moves upward and fills the pores in the higher layers of the model Arrokoth.

The team claims that this would create an atmosphere inside Arrokoth's body, stopping more gas from escaping. When a comet with such a subterranean atmosphere approaches near the sun again and sheds more surface material, the gas quickly escapes and bursts forth in a dramatic eruption.

The results contradict earlier theories of the evolution of Kuiper Belt objects, which have had difficulty explaining what happens to frozen volatiles in these frigid, far-off objects. The models relied upon may have overestimated the duration for which Kuiper Belt objects can sustain volatiles in general, especially water and carbon monoxide.

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What Is Arrokoth?

Arrokoth is a tiny Kuiper Belt object. In Powhatan/Algonquian, Arrokoth means "sky." It is known by its original identification (486958) 2014 MU69 and moniker Ultima Thule.

The science team aboard NASA's New Horizons spacecraft used the Hubble Space Telescope to find Arrokoth in 2014, making it the most basic and farthest-off object ever investigated by a spacecraft.

On Jan. 1, 2019, New Horizons passed past Arrokoth and captured pictures depicting a double-lobed object resembling a flattened snowman. Furthermore, it is much redder than Pluto. The largest surprise of the flyby was the object's peculiar shape, unlike any that had ever been observed. There is nothing comparable to it in any other solar system.