Kuiper Belt Objects ( KBOs ) are generally very faint and can not in practice be monitored with a well-sampled long-term light curve ; so our discovery of the bright KBO 2000 EB _ { 173 } offers an excellent opportunity for synoptic studies .
We present a well-sampled photometric time series ( 77 R magnitudes and 29 V magnitudes on 78 nights ) over a 225-day time span centered on the 2001 opposition .
The light curve ( corrected to the year 2001 opposition distance ) varies from 19.11 to 19.39 mag with a single peak that is smooth , time symmetric , and coincident with opposition .
All variations in the light curve are consistent with a linear opposition surge ( R _ { OPP } = 19.083 + 0.125 \alpha , where \alpha is the solar phase angle ) , while any rotational modulation must have a peak-to-peak amplitude of less than 0.097 mag .
This is the first measured opposition surge for any KBO ( other than Pluto ) .
The V R color is 0.63 \pm 0.02 , with no apparent variation with phase at the few percent level .
With R = 19.11 at opposition , 2000 EB _ { 173 } remains the brightest known KBO and a prime target for future photometric and spectroscopic studies .