Astronomy: Body double

The Galileo spacecraft's discovery of a satellite, Dactyl, orbiting the asteroid Ida, sparked a search for similar binary asteroids. Since then, other main belt and near-Earth binaries have been found. Another reservoir of minor planets is the Kuiper belt, a large population of small bodies beyond Neptune. Ground-based and HST observations reveal 1998 WW31 as the 'first' binary transneptunian object, after the Pluto/Charon pair. Since this discovery at least six other pairings have been identified.

letters to nature
The binary Kuiper-belt object 1998 WW31
CHRISTIAN VEILLET, JOEL WM. PARKER, IAN GRIFFIN, BRIAN MARSDEN, ALAIN DORESSOUNDIRAM, MARC BUIE, DAVID J. THOLEN, MICHAEL CONNELLEY & MATTHEW J. HOLMAN
Nature 416, 711–713 (18 April 2002)
| First Paragraph | Full Text | PDF (217 K) |

news and views
Astronomy: Worlds of mutual motion
JEAN-LUC MARGOT
Two asteroids beyond Neptune have been found to orbit one another. This binary system in the Kuiper belt shows marked differences from binary objects elsewhere in the Solar System.
Nature 416, 694–695 (18 April 2002)
| Full Text | PDF (193 K) |

Rocks twirl in remote two-step

18 April 2002 table of contents