A duo of planetary scientists from Brown University and the SETI Institute has found that the Kuiper Belt object (486958) Arrokoth, which was the target of the January 1, 2019 flyby by NASA’s New Horizons mission, may have ancient ices stored deep within it from when the object first formed billions of years ago. Using a new model they developed to study how comets evolve, the researchers suggest this feat of perseverance isn’t unique to Arrokoth but that many objects from the Kuiper Belt may also contain the ancient ices they formed with.
“We’ve shown here in our work, with a rather simple mathematical model, that you can keep these primitive ices locked deep within the interiors of these objects for really long times,” said Dr. Sam Birch, a planetary scientist at Brown University.
“Most of our community had thought that these ices should be long lost, but we think now that may not be the case.”
Until now, planetary scientists had a hard time figuring out what happens to ices on these space rocks over time.
The new study challenges widely used thermal evolutionary models that have failed to account for the longevity of ices that are as temperature sensitive as carbon monoxide.
The model Dr. Birch and SETI Institute researcher Orkan Umurhan created for the study accounts for this change and suggests that the highly volatile ices in these objects stick around much longer than was previously thought.
“We are basically saying that Arrokoth is so super cold that for more ice to sublimate — or go directly from solid to a gas, skipping the liquid phase within it — that the gas it sublimates into first has to have travel outwards through its porous, sponge-like interior,” Dr. Birch said.
“The trick is that to move the gas, you also have to sublimate the ice, so what you get is a domino effect: it gets colder within Arrokoth, less ice sublimates, less gas moves, it gets even colder, and so on.”
“Eventually, everything just effectively…
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