Letter to the Editor

The mass of Himalia from the perturbations on other satellites

¹ Sternberg astronomical institute, 13 Universitetskij prospect, 119992 Moscow, Russia e-mail: emelia@sai.msu.ru
² Institut de mécanique céleste et de calcul des éphémérides – Observatoire de Paris, UMR 8028 du CNRS, 77 avenue Denfert-Rochereau, 75014 Paris, France

Received: 20 May 2005
Accepted: 12 June 2005

Abstract

We made an attempt to determine the masses of two Jupiter's outer satellites, Himalia (J6) and Pasiphae (J8), on the basis of their perturbations on other satellites. For this, all observations available in the database of the Natural Satellite Data Center (NSDC, http://lnfm1.sai.msu.ru/neb/nss/index.htm) were used. New value of the product of Himalia's mass by the gravity constant was obtained (the uncertainty of one-sigma is given). We demonstrated that the determination of the mass is possible only because of one close approach of Himalia (J6) and Elara (J7) which took place on July 15th, 1949, when the distance between them was 65 031 km. Independent determination of Himalia's mass allowed to obtain the relationship between assumed values of density and geometric albedo of this satellite. Researches based on simulated observations showed that such a determination of the mass for the satellite Pasiphae (J8) is impossible.