Statistical and numerical study of asteroid orbital uncertainty

¹ Shanghai Astronomical Observatory, 80 Nandan Road, The Chinese Academy of Science, 200030 Shanghai, PR China
² IMCCE – Observatoire de Paris, UPMC, UMR 8028 CNRS, 77 avenue Denfert-Rochereau, 75014 Paris, France
e-mail: desmars@imcce.fr; bancelin@imcce.fr; hestro@imcce.fr; thuillot@imcce.fr

Received: 11 January 2013
Accepted: 12 March 2013

Abstract

Context. The knowledge of the orbit or the ephemeris uncertainty of asteroids presents a particular interest for various purposes. These quantities are, for instance, useful for recovering asteroids, for identifying lost asteroids, or for planning stellar occultation campaigns. They are also needed for estimating the close approach of near-Earth asteroids, and the subsequent risk of collision. Ephemeris accuracy can also be used for instrument calibration or for scientific applications.

Aims. Asteroid databases provide information about the uncertainty of the orbits and allow the measure of the quality of an orbit. This paper analyses these different uncertainty parameters and estimates the impact of the different measurements on the uncertainty of orbits.

Methods. We dealt with two main databases, astorb and mpcorb, that provide uncertainty parameters for asteroid orbits. Statistical methods were used to estimate orbital uncertainty and to compare them with parameters from the databases. Simulations were also generated to deal with specific measurements such as the future Gaia mission or present radar measurements.

Results. Relations between the uncertainty parameter and the characteristics of the asteroid (orbital arc, absolute magnitude, etc.) are highlighted. Moreover, a review of the different measuments are compiled and their impact on the accuracy of the orbit is also estimated.