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D. Rabinowitz (Yale University), B. Schaefer (U. Texas, Austin)
Here we report measurements of the phase curve for 2000 EB173, a bright Plutino with opposition magnitude R=19.1 and red color V-R=0.57+/-0.05 discovered by the QUEST survey[1]. We made all observations from November 2000 to May 2001 with 1.0-meter Yale Telescope at Cerro Tololo, Chile using Johnson V and R filters and CCD. Exposures times were short (<5 minutes) to allow small-aperture photometry, calibrated with secondary standards in each field which we observed on photometric nights. The phase curve, measured from phases of 0.28 to 1.9 degrees, is linear with a slope of 0.165 mag/deg. Assuming a curve of the form defined by Bowell et al. [2], a minimal chi-squared fit to our R observations yields H=4.99+/-0.01, G=0.16+/-0.06 (assuming V-R=0.57). We see no evidence for rotational modulation greater than 0.05 magnitudes, and the V-R color we measure at phase angle 1.8 degrees is consistent with earlier measurements. The phase curve is unusually steep compared to other icy bodies observed in the outer solar system [3].
[1] Ferrin, I. et al., ApJ 548, L243-247, 2001; [2] Bowell, E. et al., in Asteroids II (eds. Binzel, R. P., Gehrels. T., and Matthews, M.S). 524-556 (U. Arizona Press Tucson, 1989) ; [3] Schaefer, B. and Tourtellotte, S., Icarus 151, 112-117, 2001.