Retrograde orbits excess among observable interstellar objects

Abstract

In this work we investigate the orbital distribution of interstellar objects (ISOs), observable by the future wide-field National Science Foundation Vera C. Rubin Observatory (VRO). We generate synthetic population of ISOs and simulate their ephemerides over a period of 10 years, in order to select those which may be observed by the VRO, based on the nominal characteristics of this survey. We find that the population of the observable ISOs should be significantly biased in favor of retrograde objects. The intensity of this bias is correlated with the slope of the size-frequency distribution (SFD) of the population, as well as with the perihelion distances. Steeper SFD slopes lead to an increased fraction of the retrograde orbits, and also of the median orbital inclination. On the other hand, larger perihelion distances result in more symmetric distribution of orbital inclinations. We believe that this is a result of the Holetschek effects, which is already suggested to cause observational bias in orbital distribution of long period comets. The most important implication of our findings is that an excess of retrograde orbits depends on the sizes and the perihelion distances. Therefore, the prograde/retrograde orbits ratio and the median inclination of the discovered population could, in turn, be used to estimate the SFD of the underlying true population of ISOs.

References in corpus (18)

• Formation of planetary debris discs around white dwarfs I: Tidal disruption of an extremely eccentric asteroid
• Interstellar Interloper 1I/2017 U1: Observations from the NOT and WIYN Telescopes
• An Observational Upper Limit on the Interstellar Number Density of Asteroids and Comets
• Initial Characterization of Interstellar Comet 2I/2019 Q4 (Borisov)
• The Natural History of 'Oumuamua
• Origin and evolution of long-period comets
• APO Time Resolved Color Photometry of Highly-Elongated Interstellar Object 1I/'Oumuamua
• Evaporation and Accretion of Extrasolar Comets Following White Dwarf Kicks
• 1I/`Oumuamua as a Tidal Disruption Fragment From a Binary Star System
• Realistic Detectability of Close Interstellar Comets
• The Orbit and Size-Frequency Distribution of Long Period Comets Observed by Pan-STARRS1
• CO-Driven Activity in Comet C/2017 K2 (PANSTARRS)
• C/2010 U3 (Boattini): A Bizarre Comet Active at Record Heliocentric Distance
• On the Anomalous Acceleration of 1I/2017 U1 `Oumuamua
• A search for the origin of the interstellar comet 2I/Borisov
• Modeling the Nearly Isotropic Comet Population in Anticipation of LSST Observations
• The digest2 NEO Classification Code
• Dust bombardment can explain the extremely elongated shape of 1I/'Oumuamua and the lack of interstellar objects