[X] My Assistant

[Holder of the Tw...]

They finally found a chunk of something coming into the Solar System. Something much bigger than cosmic rays or dust particles.

Asteroid/comet in hyperbolic trajectory

[Gerald]

This seems to be within the possible scenarios on the basis of the noisy data.
But lack of evidence regarding the interior appears to be a pretty thin basis to conclude "moist" in the interior.
I'd be pretty sure, that we'll also see different interpretations in the future.

[JRehling]

It seems like the number of possible hypotheses is hard to bound, but one that comes to mind would be that it is a body that was once part of another planetary system that was ejected via gravity assists and has taken a long time to cross interstellar distances.

A gravity assist adds a velocity less than the orbital velocity of the assisting (large) planet to the assisted (small) object.

For this object to get such a large velocity before arriving at our system would require some very exceptional circumstances – compared to anything in our system. It seems that the velocity of the assisting object must have been very high. So one scenario would be a double star system or a system with a hot Jupiter that accelerated a small object that got in the right place at the right time. This would necessarily imply a passage close to at least one star, although that passage could have been arbitrarily brief and the star need not necessarily be as hot as Sol.

By no means does this discussion exhaust the possibilities, but it seems to be copacetic with our knowledge of planetary systems around dwarf stars. I don't know how one could quantify the possibility that it might come from a system very atypical of ones we currently know of.