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A.C. Delsanti, O.R. Hainaut, H. Boehnhardt, C.E. Delahodde, T. Sekiguchi (ESO - Chile), R.M. West (ESO - Garching)
The current observed TNO orbital distribution shows a quite sharp cut-off at ~45AU. It is of interest to determine whether this cut-off reflects the actual mass distribution in the outer Solar System or is an observational bias. Indeed, traditional surveys were not very sensitive to TNOs at r > 50A (taking typical seeing values, and observation span of the order of 1--2h).
We have started a survey using the ESO/MPI 2.2m telescope at La Silla equipped with the Wide Field Imager 8k CCD mosaic. The originality of this survey is to have a large observation time span, leading to an increased sensitivity to TNOs at very large heliocentric distances.
In order to scan the images for moving objects, we have updated and optimized an automatic search software [1]. This program was extensively tested on synthetic data, and proved to detect all TNOs present in the data down to a level of 1.5sigma. Moreover, the code is optimized, so that it can process a series of seven 8k2 pix frames in a few minutes, allowing online processing of the data at the telescope. This paper will present the search program, as well as the results of the first observation runs, during which several distant TNOs were discovered.
[1] Hainaut, O.R. and K.J. Meech (1996); ``An automatic technique for finding faint moving objects in wide field CCD images'', Bull.AAS, Vol. 28, No. 3, 1082.
The author(s) of this abstract have provided an email address for comments about the abstract: adelsanti@eso.org