Discovery of the Bright Trans - Neptunian Object 2000 EB 173

We describe the discovery circumstances and photometric properties of 2000 EB173, now one of the brightest trans-Neptunian objects (TNOs) with opposition magnitude mR = 18.9 and also one of the largest Plutinos, found with the drift-scanning camera of the QUEST Collaboration, attached to the 1-m Schmidt telescope of the National Observatory of Venezuela. We measure B − V = 0.99± 0.14 and V −R = 0.57± 0.05, a red color observed for many fainter TNOs. At our magnitude limit mR = 20.1±0.20, our single detection reveals a sky density of 0.015 (+0.034, -0.012) TNOs per deg (the error bars are 68% confidence limits), consistent with fainter surveys showing a cumulative number proportional to 10R. Assuming an inclination distribution of TNOs with FWHM exceeding 30 deg, it is likely that one hundred to several hundred objects brighter than mR = 20.1 remain to be discovered. Universidad de los Andes, Departamento de Fisica, 5101, Mérida, Venezuela, [email protected] Yale University, Physics Department, P. O. Box 208121, New Haven CT 06520-8121 Yale University, Astronomy Department, P. O. Box 208101, New Haven CT 06520-8101 Centro de Investigaciones de Astronomı́a (CIDA), A. P. 264, 5101-A, Mérida, Venezuela Indiana University, Deptartment of Astronomy, 319 Swain West, Bloomington IN 47405 Ohio State University, Department of Astronomy, Columbus OH 43210 Carnegie Observatories, 813 Santa Barbara St., Pasadena CA 91101 Universidad de Zaragoza, Grupo de Mecanica Espacial, Zaragoza, Spain 50009 Institute of Astronomy, Madingley Road, Cambridge, CB3 OHA, England Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91109