One of my favorite new results comes from a team lead by Fathi Namouni at the Observatoire de la Côte d’Azur. In this case, rather than modeling a single object, this team modeled a group of objects and asked how they got there. In our outer solar system, we regularly see things in weird orbits, and when we see weird orbits that are somewhat similar, we give that class of objects in those orbits a name. One of these groups is the Centaurs, objects in orbits haphazardly scattered around the orbits of Saturn, Uranus, and inside Neptune’s orbit. Some of these objects are Icy Kuiper Belt and maybe Oort cloud objects that can have been flung in through three body interactions, and will eventually become short period comets. Others are rocky and harder to sort since our solar system’s rocky objects formed in the inner bits of the solar system. Well, it gets a lot easier to explain them if we look outside our system. A new paper in the Monthly Notices of the Royal Astronomical Society describes how at least 19 of these asteroids are of interstellar origins. Quite likely, these rocky bodies were purloined from nearby stars when our solar system was still forming, and they’ve been with us ever since. Once again we’re reminded, we are a mix of locally grown and imported worlds. Our solar system has a border – the Voyagers found it and pushed through it – and anything that wants to, can cross that border and visit us at any time.

More:

Interstellar asteroids found hiding in plain sight (RAS.ac.uk)

New discovery: first asteroid population from outside our solar system (CNRS)