Dumb-bell-shaped equilibrium figures for fiducial contact-binary asteroids and EKBOs

Abstract

In this work, we investigate the equilibrium figures of a dumb-bell-shaped sequence with which we are still not well acquainted. Studies have shown that these elongated and nonconvex figures may realistically replace the classic "Roche binary approximation" for modeling putative peanut-shaped or contact binary asteroids. The best-fit dumb-bell shapes, combined with the known rotational period of the objects, provide estimates of the bulk density of these objects. This new class of mathematical figures has been successfully tested on the observed light curves of three noteworthy small bodies: main-belt asteroid 216 Kleopatra, Trojan asteroid 624 Hektor and Edgeworth-Kuiper-belt object 2001 QG298. Using the direct observations of Kleopatra and Hektor obtained with high spatial resolution techniques and fitting the size of the dumb-bell-shaped solutions, we derived new physical characteristics in terms of equivalent radius and bulk density. In particular, the growing inadequacy of the radar shape model for interpreting any type of observations of Kleopatra (light curves, AO images, stellar occultations) in a satisfactory manner suggests that Kleopatra is more likely to be a dumb-bell-shaped object than a "dog-bone".

60 pages, 16 figures

References in corpus (4)

• Densities of Solar System Objects from their Rotational Lightcurves
• New determination of the size and bulk density of the binary asteroid 22 Kalliope from observations of mutual eclipses
• Angular Momemtum of Binary Asteroids: Implication for their possible origin
• Detection of Contact Binaries Using Sparse High Phase Angle Lightcurves

Cited by in corpus (8)

• (216) Kleopatra, a low density critically rotating M-type asteroid
• Compositional Constraints for Lucy Mission Trojan Asteroids via Near-Infrared Spectroscopy
• A Statistical Review of Light Curves and the Prevalence of Contact Binaries in the Kuiper Belt
• A possible dynamically Cold Classical contact binary: (126719) 2002 CC249
• Regularization of the Hill four-body problem with oblate bodies
• Surface Gravity of Rotating Dumbbell Shapes
• Close-to-fission dumbbell Jupiter-Trojan (17365) Thymbraeus
• Direct contact binary planetesimal formation from gravitational collapse