See also: Sylvia

(87) Sylvia is one of largest the Astéroïde S of the girdles principal and the first asteroid discovered to have a system made up of two other asteroids like natural satellite.

He was discovered by Norman Robert Pogson the May 16th 1866.

Physical characteristics

(87) Sylvia is of a very dark color and probably has a primary composition. The discovery of its satellites allowed very precise measurements on its mass and of its density, which is extremely low besides and indicates that the asteroid is very porous. Its volume must be made up from approximately 60% of Vide.

Its number of revolutions on him even is very fast and is about 5,18 hours (its other physical characteristics are detailed in the table opposite).

Name

The origin of this name is the object of a polemic. Two assumptions clash:

• It would come from Rhéa Silvia, the mother of the twins Rémus and Romulus, the legendary founders of Rome.
• It would have been given in the honor of Sylvie Petiaux-Hugo Flammarion, first woman of Camille Flammarion.

Satellites

(87) Sylvia is the first known asteroid which has at least two natural satellites. The latter were probably created by a collision and it is possible that there exist other satellites around (87) Sylvia, too small to be able to be currently detected.

(87) Sylvia I Romulus

Romulus, the first satellite, (provisional name: S/2001 (87) 1), was discovered the February 18th 2001 by Michael E. Brown and Jean-Luc Margot thanks to the telescope Keck II of the Observatoire of Mauna Kea to Hawaii.

It measures approximately 18±4 km of diameter, orbits at a distance from 1.356±5 km of (87) Sylvia and carries out a complete Révolution in 3,6496±0,0007 days (87,59 hours).

(87) Sylvia II Rémus

Rémus, the second satellite, (provisional name: S/2004 (87) 1), was discovered the August 9th 2005 by Franck Marchis (of the University of California to Berkeley) and Pascal Descamps, Daniel Hestroffer and Jerome Berthier (of the Observatoire of Paris), thanks to one of the 4 telescopes of 8,2 meter of the Broad Very Telescopes (VLT) southern European Observatoire (ESO).

It measures approximately 7±2 km of diameter, orbits with 706±5 km of the primary education and carries out a complete rotation in 1,3788±0,000733 days (33,09 hours).

External bonds

• compilation of the orbital elements and other data
• 1 Curve of luminosity of (87) Sylvia
• 2 Albedo of (87) Sylvia
• Discovered first system asteroidal triple
• Discovered first system asteroidal triple