Physical model of asteroid (130) Elektra based on adaptive optics images obtained by the VLT/SPHERE instrument

Abstract

Using the ADAM software package, the shape model of the asteroid (130) Elektra was reconstructed. The model is based on 60 lightcurves from the DAMIT database, 46 AO images obtained by the NIRC2 and SPHERE in- struments and two occultations. The best-fit model assigns Elektra the vol- ume of (4.3 ± 0.1) × 106 km3 . After that, using the Xitau program, the orbital model of the two moons S/2014 1 and S/2003 was constructed. It is based on astrometry of the moons reduced from the 2014 and 2019 SPHERE images of Elektra. The model is a dipole non-Keplerian one, which resulted in an adjustment to the periods of the two moons to P1 = (1.2185 ± 0.0004) d & P2 = (5.3015 ± 0.0001) d. The main result is the more precise mass of Elektra at (6.59 ± 0.08) × 1018 kg, which revises the bulk density to ̄ρ = (1.533 ± 0.066) g cm−3 .

Pomocí softwarového balíku ADAM byl zrekonstruován model tvaru aste- roidu (130) Elektra. Model je zaloen na 60 svtelných kivkách z databáze DA- MIT, 46 AO snímcích získaných pístroji NIRC2 a SPHERE a dvou zákrytech. Nejvhodnjí model pidluje Elekte objem (4, 3 ± 0, 1) × 106 km3 . Dále byl, pomocí programu Xitau, zkonstruován orbitální model dvou m- síc S/2014 1 a S/2003. Ten je zaloen na astrometrii tchto msíc vypracované ze SPHERE snímk Elektry z let 2014 a 2019. Model je dipólový a nekeple- rovský, co vedlo k úprav period tch dvou msíc na P1 = (1,2185 ± 0,0004) d & P2 = (5,3015 ± 0,0001) d. Hlavním výsledkem je pesnjí hmotnost Elektry pi (6,59 ± 0,08) × 1018 kg, která reviduje objemovou hustotu na ̄ρ = (1,533 ± 0,066) g cm−3 .