This is the fourth comet Gröller has discovered, but given its extraordinary distance, it was the most exciting find, he says ...

Because of its hyperbolic orbit, there was first thought to be a possibility that A117uUD was an extrasolar object. Nevertheless, more investigation verified that it originated in our solar system.

Instead, its orbit would have been hyperbolic — i.e. not closed around the sun — and it would have come from somewhere beyond the solar system. Astronomers have seen objects with hyperbolic ...