Starship Asterisk*

Conceptual diagram of this research. Researchers calculated the typical paths of long-orbit comets (blue) perturbed by a passing gas-giant-sized object (white) and objects of interstellar origin (red). (Credit: NAOJ)

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Astronomers at the National Astronomical Observatory of Japan (NAOJ) have analyzed the paths of two objects heading out of the Solar System forever and determined that they also most likely originated from outside of the Solar System. These results improve our understanding of the outer Solar System and beyond.

Not all comets follow closed orbits around the Sun. Some fly through the Solar System at high speed before heading out to interstellar space, never to return. Although it is simple to calculate where these comets are going, determining where they came from is more difficult.

There are two possible scenarios. In the first scenario, a comet is originally in a stable orbit far from the Sun, but gravitational interactions with a passing object pull the comet out of its orbit. The comet then falls into the inner Solar System where it can be observed before being flung out into interstellar space. In the second scenario, a comet originates someplace very far away, perhaps a different planetary system, and as it flies through interstellar space, by random chance it passes through the Solar System once before continuing on its way. ...

• Monthly Notices of the RAS 492(1):268 (Feb 2020) DOI: 10.1093/mnras/stz3153
• arXiv.org > astro-ph > arXiv:1911.04524 > 11 Nov 2019