A study of the perturbations on Uranus

The aim of this investigation was to develop an analytical pro cedure which could predict the existence of a trans-Plutonian planet and to determine if numerical methods, implemented on an Apple lie computer, could be used to estimate the orbital elements, mass and present position of the planet. The probe planet was chosen as Uranus because of its close proximity to the unknown planet and because the data set for Uranus is the best of the outer, known planets. The data were obtained from the U.S. Naval Observatory; they consist of the rsiduals of Uranus in right ascension and declination from 1690 to 1977. The residuals were calculated by the Jet Propulsion Laboratory. FORTRAN programs were written to implement the theoretical method. It was determined that the Apple lie, single-precision calculations pro duced unacceptable round-off errors. Therefore, a larger, double-precision, computer is required to run the programs. Further, during the course of this investigation it was discovered that the mass uncertainty of the planet Neptune introduced errors which rendered the procedure developed here unusable. The uncertainty in the mass of Neptune will not improve until 1989 when the Voyager probe makes a close approach to the planet. Therefore, the prediction of a trans-Plutonian planet based on the perturbation analysis of the residuals of Uranus will not be feasible before 1989.