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J-M. Petit (Obs. de Besancon), B. Gladman (Obs. de la Cote d'Azur), JJ Kavelaars (McMaster Univ.), M. Holman (Harvard - Smithonian), J. Parker (SwRI), T. Grav (Univ. of Oslo), Ch. Veillet (CFHT)
We present the design of a large-scale, long-term trans-neptunian object (TNO) discovery and tracking program. To understand the dynamical structure of the Kuiper Belt requires the acquisition of large (hundreds to a thousand) UNBIASED sample of objects which have been observed at several oppositions. Although a set of well-established orbits exist in the Minor Planet Center database, this sample is biased to an unknown level by 'follow-up bias'. That is, when objects are discovered their poorly constrained orbits are often assumed to be like those of other known objects; this means that follow-up observations are targeted at the resulting ephemeris and therefore the objects most likely to be tracked are those which are on orbits corresponding to the initial assumptions.
We have attempted to avoid this effect by discovering a set of trans-Neptunian objects in well-characterized surveys (in which the sensitivity as a function of apparent magnitude and rate of motion are determined). Once such objects receive MPC designations, we have gone to great efforts to track every single one of these detections. The follow-up telescope time to do this is roughly a factor of 5 greater than the discovery effort, but this produces an orbit database WITHOUT BIAS. We will present the initial results of this strategy as applied to a sample of objects detected at the Canada-France Hawaii telescope. These objects now have 3-opposition arcs and the orbital distribution of this set of TNOs will be compared and contrasted to the larger MPC database as a whole to illustrate the biases present. We estimate the 'plutino fraction' (the fraction of objects between 30 and 50 AU that are in the 2:3 mean-motion resonance with Neptune) to be at most a few percent. A companion talk will discuss several of the most interesting objects whose orbits have been determined during the course of this program.
The author(s) of this abstract have provided an email address for comments about the abstract: petit@obs-besancon.fr