Author/Authors :
Marchis، نويسنده , , F. and Vachier، نويسنده , , F. and Durech، نويسنده , , J. and Enriquez، نويسنده , , J.E. and Harris، نويسنده , , A.W. and Dalba، نويسنده , , P.A. and Berthier، نويسنده , , J. and Emery، نويسنده , , J.P. and Bouy، نويسنده , , H. and Melbourne، نويسنده , , J. K. Stockton، نويسنده , , A. and Fassnacht، نويسنده , , C.D. and Dupuy، نويسنده , , T.J. and Strajnic، نويسنده , , J.، نويسنده ,
Abstract :
From a set of adaptive optics (AO) observations collected with the W.M. Keck telescope between August and September 2009, we derived the orbital parameters of the most recently discovered satellites of the large C-type asteroid (93) Minerva. The satellites of Minerva, which are approximately 3 and 4 km in diameter, orbit very close to the primary (∼5 and ∼8 × Rp and ∼1% and ∼2% × RHill) in a circular manner, sharing common characteristics with most of the triple asteroid systems in the main-belt. Combining these AO observations with lightcurve data collected since 1980 and two stellar occultations in 2010 and 2011, we removed the ambiguity of the pole solution of Minerva’s primary and showed that it has an almost regular shape with an equivalent diameter Deq = 154 ± 6 km in agreement with IRAS observations. The surprisingly high bulk density of 1.75 ± 0.30 g/cm3 for this C-type asteroid, suggests that this taxonomic class is composed of asteroids with different compositions, For instance, Minerva could be made of the same material as dry CR, CO, and CV meteorites. We discuss possible scenarios on the origin of the system and conclude that future observations may shine light on the nature and composition of this fifth known triple main-belt asteroid.
Keywords :
Asteroids , Satellites of asteroids , adaptive optics , Orbit Determination , interiors
