Astrometric observations of Phoebe from 2010 to 2019 based on Gaia DR3

Abstract

A total of 914 positions of Phoebe were collected from 2010 to 2019 with three different telescopes, which were the 1.56 m telescope at the Sheshan station of Shanghai Astronomical Observatory, the 1.0 m telescope at the Kunming station of Yunnan Astronomical Observatory and the 2.4 m telescope at the Lijiang station of Yunnan Astronomical Observatory. Based on Gaia DR3 catalogue, all CCD observation images were reduced with the suitable plate model. We compared our observations to the theoretical positions retrieved from IMCCE ephemeris online service with satellite ephemeris of Desmars et al. (2013) model and planetary ephemeris DE441. The result shows that the mean residuals are 19 mas and 24 mas in right ascension and declination, the standard deviation of residuals are 77 mas and 67 mas in right ascension and declination. These precise observations of Phoebe over 10 year period will be important for improving the orbital parameters of Phoebe.