Beyond the surface
Alan Stern, principal investigator of the New Horizons mission to Pluto and Arrokoth, tells Astronomy he’s impressed by the ingenuity the researchers have shown in the paper. “I think they have a very innovative idea,” he says. However, Stern remains cautious: “I am not sure the surface telltales are likely to be as dramatic as the paper describes."
Stern notes the “breezes” described in the paper would be only one of the processes occurring during the earliest phases of Arrokoth’s formation. “There was a slow tail to accretion, to thermal evolution, to space weathering by the radiation environment, [to] effects in the disk which was still dissipating," he says. "All this was going on at once and at different time scales.”
He also notes a need for follow-up work to determine whether “other Kuiper Belt objects would be similarly affected, and how we would go about determining if this is, in fact, what actually happened — either with future missions to the Kuiper Belt, or by observing comet belts around T Tauri stars and looking for telltales of this kind of process.
“What remains to be seen with more detailed modeling or with these observations — either future missions or observations of stars — is to determine just how important this [surface sublimation] process really is," he adds.
No matter what, Arrokoth still remains the most pristine relic of the solar system's formation ever closely examined by a spacecraft. And even if cryogenic breezes altered its surface after its initial formation, it's still about as old of a surface as we've ever seen up close. So, as researchers continue to pour over the data produced by New Horizons' historic flyby, many more surprising results are sure to follow.
Joel Davis (@joeldaviswriter) is a frequent contributor to Astronomy.