Phoebe's orbit from ground-based and space-based observations

Abstract

The ephemeris of Phoebe, the ninth satellite of Saturn, is not very accurate. Previous dynamical models were usually too simplified, the astrometry is heterogeneous and, the Saturn's ephemeris itself is an additionnal source of error. The aim is to improve Phoebe's ephemeris by using a large set of observations, correcting some systematic errors and updating the dynamical model. The dynamical model makes use of the most recent ephemeris of planets and Saturnian satellites. The astrometry of Phoebe is improved by using a compilation of ground-based and space-based observations and by correcting the bias in stellar catalogues used for the reduction. We present an accurate ephemeris of Phoebe with residuals of 0.45 arcsec and with an estimated accuracy of Phoebe's position of less that 100 km on 1990-2020 period.

10 pages, 9 figures, accepted by A&A

References in corpus (1)

• The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)

Cited by in corpus (6)

• Astrometric positions for 18 irregular satellites of giant planets from 23 years of observations
• New orbits of irregular satellites designed for the predictions of stellar occultations up to 2020, based on thousands of new observations
• The first observed stellar occultations by the irregular satellite (Saturn IX) Phoebe and improved rotational period
• The orbits of outer planetary satellites using the Gaia data
• Complementary astrometry of Cassini Imaging Science Subsystem Images of Phoebe
• Astrometric Reduction of Saturnian Satellites with Cassini-ISS Images Degraded by Trailed Stars