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D. Rabinowitz (Yale University), Quasar Equatorial Survey Team
Asteroid 2000 EB 173 is currently the brightest known TNO with opposition magnitude R<19.2, and presumably the largest known Plutino with absolute magnitude H=4.9 (1/4 the size of Pluto assuming low albedo 0.04). We discovered the object in a one-night search (2000 March 15 UT) covering 66.8 degrees using the 1-m Schmidt at Llano del Hato, Venezuela. Our collaboration, known as the Quasar Equatorial Survey Team  (QUEST), has designed and constructed for this telescope a 8k x 8k array of CCDs which we use in drift-scanning mode to scan areas 2.36 deg wide in Dec and up to 165 deg wide in RA through a sequence of 4 broad-band filters. Normally, we cover the same area on a nightly basis to find quasars, supernovae, and other variable objects. To find TNOs, we limited the search to an area 28.3 deg wide in RA centered at RA = 13.249 h, Dec = -1.1 deg, which we scanned twice with a 4 hour separation. Later, we used software to subtract a reference image of the same area recorded on previous nights and to thereby isolate candidate images of TNOs. From detections of main-belt asteroids identified in the same manner, we measure our 50% detection limit at R=20.0 ± 0.2. Our observation of one TNO brighter than this limit favors the magnitude-frequency reported by Jewitt et al. over the relatively steep distribution reported by Gladman et al., and points to a continuous distribution up to Pluto-sized objects. Our BVRI photometry in February, March and June reveals a stellar seeing profile and a steep red reflectance spectrum typical of fainter TNOs, except for a possible absorption in the I band. There is no apparent variability greater than 10% in the February and March observations, but the June observations are fainter by \approx0.3 magnitudes. This requires either an unusually steep phase curve post opposition, or else peculiar variability.
 Schaefer, B. et al., AJ 524, L103 (1999);  Snyder, J. SPIE 3355, 635 (1998);  Jewitt, D., Luu, J., and Trujillo, C. AJ 115, 2125-2135 (1998);  Gladman, B. et al., AJ 116, 2042-2054 (1998);  IAUC 7459 (2000).
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