The high frequency variations in the rotation of Eros

¹ Observatoire de Paris, SYRTE, UMR 8630 du CNRS, 61 avenue de l'Observatoire, 75014 Paris, France e-mail: Jean.Souchay@obspm.fr
² Tokyo National Astronomical Observatory, Oosawa 2-21-2 Mitaka Shi, Tokyo 181-0005, Japan e-mail: Sebastien.Bouquillon@obspm.fr

Received: 1 December 2003
Accepted: 22 November 2004

Abstract

We use very precise information concerning the physical properties of the asteroid Eros 433, obtained by the NEAR probe mission, to analytically compute the modifications of its rotation on a short time scale, with a precision never reached before for an asteroid. Two kinds of components are investigated here: the free rotation and the forced one, due to the gravitational torque exerted by the Sun. Coefficients of the short periodic part of Eros' forced nutation are rather large, due to the fact that the asteroid has a significant triaxial shape. They are calculated with the same relative accuracy as the moments of inertia of the asteroid. Our results are compared with those obtained through numerical integration (Miller et al. [CITE], Icarus, 155, 3), which show high frequency oscillations of the position of Eros' axis of figure in space. Some important differences are discussed.