Eight billion asteroids in the Oort cloud


Type
Article
Change log
Authors
Shannon, A 
Jackson, AP 
Veras, D 
Abstract

The Oort cloud is usually thought of as a collection of icy comets inhabiting the outer reaches of the Solar system, but this picture is incomplete. We use simulations of the formation of the Oort cloud to show that ∼4 per cent of the small bodies in the Oort cloud should have formed within 2.5 au of the Sun, and hence be ice-free rock-iron bodies. If we assume that these Oort cloud asteroids have the same size distribution as their cometary counterparts, the Large Synoptic Survey Telescope should find roughly a dozen Oort cloud asteroids during 10 years of operations. Measurement of the asteroid fraction within the Oort cloud can serve as an excellent test of the Solar system's formation and dynamical history. Oort cloud asteroids could be of particular concern as impact hazards as their high mass density, high impact velocity, and low visibility make them both hard to detect and hard to divert or destroy. However, they should be a rare class of object, and we estimate globally catastrophic collisions should only occur about once per billion years.

Description
Keywords
comets: general, minor planets, asteroids: general, Oort cloud
Journal Title
Monthly Notices of the Royal Astronomical Society
Conference Name
Journal ISSN
0035-8711
1365-2966
Volume Title
446
Publisher
Oxford University Press (OUP)
Sponsorship
AS andMWare supported by the European Union through ERC grant number 279973. DV is supported by the European Union through ERC grant number 320964.