Discover

{{downsize|title=
'' (also written '(66391) 1999 KW4') is an Aten and Mercury-crosser asteroid discovered by LINEAR in 1999.
has a moon orbiting it. The moon, designated 'S/2001 (66391) 1' or '1999 KW4 Beta' is ~360 m in diameter, and orbits 'Alpha' in 0.758 d (16 hours) at a distance of 2.6 km. The presence of a companion was suggested by photometric observations made June 19-27, 2000 by Petr Pravec and Lenka Šarounová at Observatoř Ondřejov (Ondřejov Observatory) and was confirmed by radar observations from Arecibo Observatory from May 21-23, 2001 by Lance A. M. Benner, Steven J. Ostro, Jon D. Giorgini, Raymond F. Jurgens, Jean-Luc Margot and Michael C. Nolan, announced on May 23, 2001.
The shapes of the two bodies and their dynamics are complex.^[1] Among other bizarre properties, the equatorial regions of Alpha are very close to breakup: raising a particle a meter above the surface would put it into orbit around the object.

Contents

References

References

1. NASA Jet Propulsion Laboratory Asteroid Radar Research, retrieved May 32007


★ Johnston, Wm. Robert, ed. (66391) 1999 KW4 January 72007, retrieved May 32007

★ Margo, Jean-Luc, Another radar image of November1999, retrieved May 32007