Asteroid (66391) 1999 KW4

KW4 MOVIES:

Four-frame movie (top frames show views of the entire system from above, bottom frames show Alpha as seen from Beta and Beta as seen from Alpha):

KW4 PICTURES (gzipped 300-dpi unless otherwise noted):

Collage of frames from the "View from Earth" movie

Collage of frames from the "View from Earth" movie

Partial eclipse of Alpha by Beta (from the "Alpha viewed from Beta" movie (72 dpi) 300-dpi version

Alpha's surface dynamical quantities: The equator has minimum potential energy (top), widely varying effective gravitational slopes (middle), and nearly vanishing total acceleration (bottom).

Ostro et al. Fig. 1: Single-date, multi-run sums of delay-Doppler images.

Ostro et al. Fig. 2: Examples of images and fit results. Each three-frame horizontal collage shows an Arecibo radar image used in the estimations, the corresponding image synthesized from the shape model, and a plane-of-sky view of that model.

Ostro et al. Fig. 3: Principal-axis views of the Alpha and Beta shape models, color-coded for effective gravitational slope.

Scheeres et al. Fig. 1 (72 dpi). Evolution of KW4's orbit (A) semimajor axis and (B) eccentricity over 200 hours, computed for the relaxed and excited system.

Scheeres et al. Fig. 2 (72 dpi). (A) Rotational angular velocity and (B) total angular acceleration of Beta, shown in the Beta fixed frame, for the relaxed and excited cases. (C) Alpha's orbit in a Beta-fixed frame. The large y variations are due primarily to Beta's attitude libration about the Beta-Alpha line.

Scheeres et al. Fig. 3 (72 dpi). Curves of constant geopotential about Alpha (A) without and (B) with Alpha's pole-on shape superimposed. Four equilibrium points, orbits that are stationary in the frame rotating with Alpha, are indicated by "e" and lie just at the body's surface. Alpha's surface lies outside the innermost curve, defined for the equilibrium point with the lowest potential value.

Scheeres et al. Fig. S2: Effective gravitational slopes on Alpha with arrows pointing in the direction of steepest descent. The natural flow direction from both Northern and Southern hemispheres is towards the equator. Slopes range from zero (blue) to 70 deg (red).

Scheeres et al. Fig. S3 (144 dpi): Surface acceleration on Alpha. Note the near vanishing of acceleration along the equator.

Ostro et al. Fig. S3 (pdf): Root-reduced chi-square for the barycenter delay residuals (Table S3) in the heliocentric orbit estimate (Table S2), as a function of the assumed Alpha/Beta mass ratio.

KW4 MATHEMATICS:

In each picture, each three-frame horizontal collage shows a radar image used in the estimations, the corresponding image synthesized from the shape model, and a plane-of-sky (POS) view of that model. The Set_Frame identifier corresponds to the images listed in the above tables. Each three-frame collage consists of three squares with 2.0-km sides for Alpha and 0.8-km sides for Beta. In the delay-Doppler images, the radar is toward the top and the object rotates counterclockwise. In the POS frames, north is toward the top and the arrow represents the spin vector.