Planetary Radar 759
FIGURE 20 Radar-derived shapes of (from top to bottom) main-belt asteroid 216 Kleopatra (maximum model
dimension 217 km) and the near-Earth asteroids 4179 Toutatis (4.60 km) and 6489 Golevka (0.685 km),
color-coded for gravitational slope (degrees), defined as the acute angle a plumb line would make with the local
surface normal. Uniform internal density is assumed.lightcurves, suggest that between 10 and 20% of PHAs are
binary systems.
For 2000 DP107, with an 800-m primary and a 300-m
secondary, the orbital period of 1.767 days and orbital semi-
major axis of 2620+160 m yield a bulk density of 1.7+1.1
gcm−^3 for the primary. For 66391 (1999 KW4), very high-
SNR, high-resolution delay–Doppler images characterized
the components and their dynamics in detail (Fig. 23). The
resemblance of the primary to a canonical oblate spheroid
is striking. For 1998 ST27, the orbital period is several days,
the semimajor axis could be as large as 7 km, and the rota-
tion period of the secondary is more than an order of mag-
nitude shorter than its orbital period, the first such case
among binary NEAs. 1998 ST27 and the somewhat similar