Precise CCD positions of Triton in 2014–2016 using the newest Gaia DR1 star catalogue

Abstract

755 new CCD observations during the years 2014–2016 have been reduced to derive the precise positions of Triton, the first satellite of Neptune. The observations were made by the 1-m telescope at Yunnan Observatory over 15 nights. The positions of Triton are measured with respect to the stars in Gaia DR1 star catalogue. The theoretical position of Triton was retrieved from the Jet Propulsion Laboratory (JPL) Horizons System that includes the satellite ephemeris nep081xl, while the position of Neptune was obtained from the JPL ephemeris DE431mx. Our results show that the mean (O − C)s (observed minus computed) are 0.042 and −0.006 arcsec in right ascension and declination, respectively. The dispersions of our observations are estimated at about 0.012 arcsec in each direction.