First Exoplanets, Now Exoconets

Astronomers have now detected clouds of comets orbiting other stars, just as the Oort Cloud of at least potential comets orbits the Sun.  The finding is one bit of evidence that scientists do in fact understand, in broad terms, how planetary systems form.

Another bit of evidence along that line is that the compositions of comets, here and there, are largely the same.  In both cases, elements like olivine, which had to form in close to the star, has been flung into the depths of the star system, and current theory explains that process.