We present a new non-convex model of the 90 Antiope binary asteroid , derived with a modified version of the SAGE ( Shaping Asteroids with Genetic Evolution ) method using disk-integrated photometry only .
A new variant of the SAGE algorithm capable of deriving models of binary systems is described .
The model of 90 Antiope confirms the system ’ s pole solution ( \lambda = 199 ^ { \circ } , \beta = 38 ^ { \circ } , \sigma = \pm 5 ^ { \circ } ) and the orbital period ( 16.505046 \pm 0.000005 h ) .
A comparison between the stellar occultation chords obtained during the 2011 occultation and the projected shape solution has been used to scale the model .
The resulting scaled model allowed us to obtain the equivalent radii ( R _ { 1 } = 40.4 \pm 0.9 km and R _ { 2 } = 40.2 \pm 0.9 km ) and the distance between the two system components ( 176 \pm 4 km ) , leading to a total system mass of ( 9.14 \pm 0.62 ) \cdot 10 ^ { 17 } kg .
The non-convex shape description of the components permitted a refined calculation of the components ’ volumes , leading to a density estimation of 1.67 \pm 0.23 g cm ^ { -3 } .
The intermediate-scale features of the model may also offer new clues on the components ’ origin and evolution .