Retrograde orbits excess among observable interstellar objects
Abstract
In this work we investigate the orbital distribution of interstellar objects (ISOs), observable by the future widefield 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 sizefrequency 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 Holetschek's 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.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 May 2020
 DOI:
 10.1093/mnras/staa1378
 arXiv:
 arXiv:2005.10236
 Bibcode:
 2020MNRAS.tmp.1517M
 Keywords:

 Planetary systems;
 comets: general;
 minor planets;
 asteroids: general;
 Astrophysics  Earth and Planetary Astrophysics
 EPrint:
 doi:10.1093/mnras/staa1378