Orbit Propagation of 2008 TC3: Recent and Distant Past

Paul Chodas, Jet Propulsion Laboratory, Pasadena, CA

The reconstructed orbit of 2008 TC3 is by far the most precisely determined of any observed bolide. With an observed data arc covering a time interval of 19.1 hours, starting with the discovery at only 1.3 times the lunar distance from Earth, and including several hundred observations in total, the observational constraints on the trajectory are very strong. Topocentric parallax of as much as 15 degrees is present in the data and the rates of motion were as high as 13.4 arcsec/s prior to the object's disappearance into the Earth's umbra. A careful assessment of the statistics of the astrometric errors was therefore imperative. The propagation of this orbit into the past reveals a reasonably accurate recent history going back as far as 1961, when an Earth close approach at 0.18 0.12 AU scatters the back predictions to the extent that only statistical characterizations of the earlier trajectory are possible. We compute Monte Carlo clones of the final orbit, based o n the full six-dimensional covariance, to investigate the range of possible motion. With this approach we find that over the last ~2000 years, 95% of the possible clones maintain orbits within 0.1 AU of the impacting orbit. Not surprisingly, over this short a time frame there is no dynamical evidence for a genetic relationship with any potential parent bodies.