  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 ($\lambda=199^{\circ}$,
$\beta=38^{\circ}$, $\sigma=\pm5^{\circ}$) 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 ($R_{1}=40.4\pm0.9$ km and $R_{2}=40.2\pm0.9$ km) and the distance
between the two system components ($176\pm4$ km), leading to a total system
mass of ($9.14\pm0.62$)$\cdot10^{17}$ kg. The non-convex shape description of
the components permitted a refined calculation of the components' volumes,
leading to a density estimation of $1.67\pm0.23$ g cm$^{-3}$. The
intermediate-scale features of the model may also offer new clues on the
components' origin and evolution.
