Publication Date:
2013-11-30
Description:
A new model of motions of the five main Uranian satellites is developed. The model is based on all published observations made since the dates of the satellites’ discoveries until 2008. The corresponding periods are 220 yr for Titania and Oberon , 160 yr for Ariel and Umbriel and 60 yr for Miranda . To fit the parameters of the satellites’ motion, 30 139 observations were used, including those made by the Voyager 2 spacecraft as well as astrometric results of the photometric observations of mutual occultations and eclipses of the main Uranian satellites in 2007–2008. The model is elaborated by the numerical integration of equations of motions of the satellites where all necessary perturbating factors were taken into consideration. Basing on the model, new ephemerides of the main Uranian satellites were generated for the period from 1787 to 2031. The ephemerides are put to the MULTI-SAT ephemeris server. The root-mean-square residual of observed topocentric positions of the satellites and their ephemeris positions is 0.43 arcsec. Taking into account the weighting factors of the observations, this value is 0.12 arcsec. An attempt is also made to define from observations the parameters of the mechanical energy dissipation of the satellites’ motion. The dissipation can be caused by both tides in the planet and by the tides in the satellites’ bodies. Approximate values of the quadratic terms in the orbital longitudes are obtained. These values are equal to –(0.64 ± 0.11) 10 –11 d –2 for Ariel , –(0.08 ± 0.24) 10 –11 d –2 for Umbriel , –(0.29 ± 0.09) 10 –11 d –2 for Titania , –(0.32 ± 0.07) 10 –11 d –2 for Oberon and –(7.56 ± 1.15) 10 –11 d –2 for Miranda . The obtained parameters reveal deceleration in the orbital motion of the satellites, which results from the influence of the tides raised on the interior of Uranus that is rotating faster than the satellites.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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