Chiron the centaur was a son of Saturn. Chiron the astronomical puzzle seems to be one too. The orbit of astronomer Charles Kowal’s latest discovery crosses the orbit of Saturn. Chiron’s perihelion (closest approach to the Sun) is 1.27 billion kilometers from the Sun—inside the orbit of Saturn. It will next reach perihelion in February of 1996. Chiron’s aphelion (furthest distance away from the Sun) is 2.8 billion kilometers—farther from the Sun than Uranus at its closest. Chiron’s and Uranus’ orbits don’t actually cross, since Chiron’s aphelion is near Uranus’ aphelion. (They would cross if Chiron’s aphelion were near Uranus’ perihelion.) Chiron was last at aphelion in November of 1970. Chiron’s orbital period is 50.7 Earth years.
Although astronomers have been able to pin down Chiron’s orbit already, they are still very unsure of its physical nature. It could be a planetoid, a large comet too far out to have a tail or a moon lost by Saturn or Uranus. Until a lot more observations are made, discussions of its nature are almost pure speculation.
Phenomena Publications, Box 6228, Toronto A, Canada is publishing an Ephemeris of Chiron for $5. The notice I have says 1936-1976 will definitely be covered, and more might be.