(20000) 2000 WR_106

T. L. Farnham, University of Texas, writes: "R- and V-band CCD photometry of (20000), obtained at the McDonald Observatory 2.1-m telescope on Jan. 24-27, shows a single-peaked rotational lightcurve with a probable period of 3.17 hr, though 2.78 and 3.67 hr cannot be ruled out. The 0.5-mag amplitude suggests that one hemisphere reflects at least 60 percent more light than the other. Less likely (with diameter about 900 km; cf. IAUC 7554), the lightcurve could be double-peaked with a 6.34-hr period, which would imply that (20000) has an axial ratio a/b >= 1.6."