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[7.04] Variability measurements of KBOs and Centaurs discovered by the Deep Ecliptic Survey

S. D. Kern, J. L. Elliot (M.I.T.)

We have begun a variability study for a selection of KBOs and Centaurs discovered by the Deep Ecliptic Survey. Our sample includes mostly objects at southern declinations, since we can advantageously observe these with the 6.5-m Baade telescope at Las Campanas Observatory using MagIC (Magellan Instant Camera). During the nights of UT 2002 July 9-13 and 17-18 we abtained measurements over a time span of 4-8 hours for 21 KBOs and Centaurs. These objects range in R magnitude between 19.3 and 23.1. Two objects exhibited particularly interesting variability: 2000QC₂₄₃ and 2000QB₂₄₃. The former is a Centaur for which we fit a period of 4.65 +/- 0.07 hours with an amplitude of 0.19 +/- 0.01 magnitudes. Fitting the data as double-peaked lightcurve yields a period of 9.30 +/- 0.14 hours. The later is a "SD-N" (Scattered Disk-Near) object with a semi-major axis of 34.6 +/- 0.1 AU and an eccentricity of 0.560 +/- 0.002. This object is variable on the timescale of 5 hours with an amplitude of 0.2 magnitudes. Of the other 19 objects, 6 are possibly variable above 0.15 magnitudes and 13 are flat below this level. This percentage of variability appears comparable to the 31% in the sample of KBOs investigated by Sheppard & Jewitt (2002 AJ, in press). This work was supported, in part, by NASA Grant NAG5-10444.

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Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.