M. Assafin, J. I. B. Camargo, R. Vieira Martins, F. Braga-Ribas, B. Sicardy, A. H. Andrei, D. N. da Silva Neto
We study large trans-neptunian objects (TNOs) using stellar occultations. We derive precise astrometric predictions for stellar occultations by Eris, Haumea, Ixion, Makemake, Orcus, Quaoar, Sedna, Varuna, 2002 TX300, and 2003 AZ84 for 2011-2015. We construct local astrometric catalogs of stars in the UCAC2 (Second US Naval Observatory CCD Astrograph Catalog) frame covering the sky path of these objects. For that purpose, during 2007-2009, we carried out an observational program at the ESO2p2/WFI (2.2 m Max-Planck ESO telescope with the Wide Field Imager) instrument. Astrometric catalogs with proper motions were produced for each TNO, containing more than 5.35 million stars covering the sky paths with 30' width in declination. The magnitude completeness is about R = 19 with a limit of about R = 21. We predicted 2717 stellar occultation candidates for all targets. Ephemeris offsets with about from 50 mas to 100 mas precision were applied to each TNO orbit to improve the predictions. They were obtained during 2007-2010 from a parallel observational campaign carried out with from 0.6 m to 2.2 m in size telescopes. This extends our previous work for the Pluto system to large TNOs, using the same observational and astrometric procedures. The obtained astrometric catalogs are useful for follow-up programs at small to large telescopes used to improve the candidate star positions and TNO ephemeris. They also furnish valuable photometric information for the field stars. For each TNO, updates on the ephemeris offsets and candidate star positions (geometric conditions of predictions and finding charts) are made available in the web by the group.
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http://arxiv.org/abs/1204.4234
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