Shape model of asteroid (130) Elektra from optical photometry and disk-resolved images from VLT/SPHERE and Nirc2/Keck

Abstract

<p>Context. Asteroid (130) Elektra belongs to one of the six known triple asteroids in the main belt, so its mass has been reliably determined.</p><p>Aims. We aim to use all available disk-resolved images of (130) Elektra obtained by the SPHERE instrument at VLT and by the Nirc2 of the Keck telescope together with the disk-integrated photometry to determine its shape model and its size. The volume can be then used in combination with the known mass to derive the bulk density of the primary.</p><p>Methods. We have applied the All-Data Asteroid Modeling (ADAM) algorithm to the optical disk-integrated data, two disk-resolved images obtained by the SPHERE instrument, and 13 disk-resolved images from the Nirc2 of the Keck telescope. We have also derived the shape model and size of Elektra.</p><p>Results. We present the shape model, volume-equivalent diameter (199 ± 7 km) and bulk density (1.60 ± 0.13 g cm<sup>-3</sup>) of the C-type asteroid Elektra.</p>