EDP Sciences
Free access
Volume 441, Number 2, October II 2005
Page(s) 815 - 818
Section Celestial mechanics and astrometry
DOI http://dx.doi.org/10.1051/0004-6361:20053160

A&A 441, 815-818 (2005)
DOI: 10.1051/0004-6361:20053160

Orbit correction without variational equations

The orbits of Caliban, 46P/Wirtanen and 67P/Churyumov-Gerasimenko
K. Aksnes1 and T. Grav2

1  Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029, Blindern 0315 Oslo, Norway
    e-mail: kaare.aksnes@astro.uio.no
2  Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
    e-mail: grav@ifa.hawaii.edu

(Received 30 March 2005 / Accepted 20 June 2005)

Differential orbit correction is performed by computing an osculating orbit from observations from which the perturbations have been subtracted. No variational equations need to be integrated except to solve for non-gravitational forces. The perturbations in the observations are obtained by subtracting a two-body orbit from an integrated, perturbed orbit. The method is used to update the orbits of the Uranian satellite Caliban and of the comets 46P/Wirtanen and 67P/Churyumov-Gerasimenko with recent observations. The method is shown to agree very well with, but is considerably faster than, the conventional method based entirely on variational equations. Algorithms are given for both methods.

Key words: celestial mechanics -- comets: general -- planets and satellites: general

© ESO 2005