The Lightcurve and Colors of Unusual Minor Planet 1996 PW

Abstract

Minor Planet 1996 PW is unusual in having the orbital characteristics of a long period comet but showing no sign of cometary activity around the time of its discovery. We present optical data which reveals a double peaked lightcurve (period 35.44 ± 0.02 hrs and amplitude 0.44 ± 0.03 magnitudes) and VRIJHK photometry which shows colors (V − R = 0.56 ± 0.04, V − I = 1.03 ± 0.06, V − J = 1.80 ± 0.05, V − H = 2.19 ± 0.05, and V − K = 2.32 ± 0.05) typical of D type asteroids and suspected bare comet nuclei. A low signal to noise reflectance spectrum in the K band shows a flat continuum with no evidence for spectral features. Image profiles from co-added frames in the R band indicate no apparent cometary activity with an implied upper limit to the dust production rate of 0.03 kg s−1.