Close Encounters of the Interstellar Kind: Examining the Capture of Interstellar Objects in Near Earth Orbit

Abstract

Recent observations and detections of interstellar objects (ISOs) passing through the solar system have sparked a wave of interest into these objects. Although rare, these ISOs can be captured into bound orbits around the Sun. In this study, we investigate the novel idea of capture of ISOs into near-Earth orbits and find that a steady population of ISOs exists among the current population of Near Earth Objects (NEOs). Using numerical simulations, we find that the capture of ISOs into near-Earth orbits is dominated by Jupiter which is $10^4\times$ more efficient in capturing ISOs compared to Earth. Captured ISOs are more likely to be in orbits with high eccentricities and low inclinations. We also investigate the stability of captured ISOs and find that they are generally unstable and have an average survival life time of $\sim 1$ Myr, consistent with lifetime of NEOs originating from outer asteroid belt, and are ejected from the solar system due to interactions with other planets or the Sun. Our results have important implications for understanding the population of ISOs in the solar system and possible future detection. We find that about one to a few $50-70$ m sized captured ISOs among NEOs would be detectable by LSST over its lifetime. By detecting and studying captured interstellar objects, we can learn about the properties and origins of such objects, and the formation and evolution of exoplanetary systems and even our solar system.

14 pages. 12 figures. New version with updated analysis. Accepted in MNRAS

References in corpus (19)

• An Observational Upper Limit on the Interstellar Number Density of Asteroids and Comets
• Initial Characterization of Interstellar Comet 2I/2019 Q4 (Borisov)
• Evidence that 1I/2017 U1 (`Oumuamua) was composed of molecular hydrogen ice
• 1I/`Oumuamua as a Tidal Disruption Fragment From a Binary Star System
• The fate of planetesimal discs in young open clusters: implications for 1I/'Oumuamua, the Kuiper belt, the Oort cloud and more
• Oort cloud Ecology II: Extra-solar Oort clouds and the origin of asteroidal interlopers
• No evidence for interstellar planetesimals trapped in the Solar System
• Acceleration of 1I/`Oumuamua from radiolytically produced H${}_2$ in H${}_2$O ice
• Destruction of molecular hydrogen ice and Implications for 1I/2017 U1 (`Oumuamua)
• Identifying Earth-impacting asteroids using an artificial neural network
• Capture of interstellar objects: a source of long-period comets
• The velocity ellipsoid in the Galactic disc using Gaia DR1
• Interstellar Meteors are Outliers in Material Strength
• Interstellar planetesimals: potential seeds for planet formation?
• Capture of interstellar objects I: the capture cross-section
• Capture of interstellar objects II: by the Solar system
• Observable Signatures of the Ejection Speed of Interstellar Objects from their Birth Systems
• The New Astronomical Frontier of Interstellar Objects
• On the Proposed Interstellar Origin of the USG 20140108 Fireball