Capture of interstellar objects: a source of long-period comets

Hands, T. O.; Dehnen, W. (2020): Capture of interstellar objects: a source of long-period comets. In: Monthly Notices of the Royal Astronomical Society, Vol. 493, No. 1: L59-L64

Abstract

We simulate the passage through the Sun-Jupiter system of interstellar objects (ISOs) similar to 1I/'Oumuamua or 2I/Borisov. Capture of such objects is rare and overwhelmingly from low incoming speeds on to orbits akin to those of known long-period comets. This suggests that some of these comets could be of extrasolar origin, in particular inactive ones. Assuming ISOs follow the local stellar velocity distribution, we infer a volume capture rate of 0.051 au(3) yr(-1). Current estimates for orbital lifetimes and space densities then imply steady-state captured populations of similar to 10(2) comets and similar to 10(5) 'Oumuamua-like rocks, of which 0.033 per cent are within 6 au at any time.

• Item Type: Journal article
• Faculties: Physics
• Subjects: 500 Science > 530 Physics
• ISSN: 0035-8711
• Language: English