Fraction of Contact Binary Trojan Asteroids

Abstract

We present the results of an optical lightcurve survey of 114 Jovian Trojan asteroids conducted to determine the fraction of contact binaries. Sparse-sampling was used to assess the photometric range of the asteroids and those showing the largest ranges were targeted for detailed follow-up observations. This survey led to the discovery of two Trojan asteroids, (17365) and (29314) displaying large lightcurve ranges (~1 magnitude) and long rotation periods (< 2 rotations per day consistent with a contact binary nature. The optical lightcurves of both asteroids are well matched by Roche binary equilibrium models. Using these binary models, we find low densities of ~600 kg/m^3 and 800 kg/m^3, suggestive of porous interiors. The fraction of contact binaries is estimated to be between 6% and 10%, comparable to the fraction in the Kuiper Belt. The total binary fraction in the Trojan clouds (including both wide and close pairs) must be higher.

13 pages, 19 figures, and 4 tables. Accepted for publication in AJ (2007 May 22)

References in corpus (8)

• Solar System Objects Observed in the SDSS Commissioning Data
• Formation of Kuiper Belt Binaries
• Population and Size Distribution of Small Jovian Trojan Asteroids
• Densities of Solar System Objects from their Rotational Lightcurves
• A low density of 0.8 g/cc for the Trojan binary asteroid 617 Patroclus
• The formation of Kuiper-belt Binaries through Exchange Reactions
• Extreme Kuiper Belt Object 2001 QG298 and the Fraction of Contact Binaries
• Formation of Kuiper-belt binaries through multiple chaotic scattering encounters with low-mass intruders

Cited by in corpus (16)

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• Physical Properties of Main-Belt Comet 176P/LINEAR
• The heart of the swarm: K2 photometry and rotational characteristics of 56 Jovian Trojan asteroids
• A Change in the Lightcurve of Kuiper Belt Contact Binary (139775) 2001 QG298
• Binary planetesimals and their role in planet formation
• 2004 TT357: A potential contact binary in the Trans-Neptunian belt
• Occultation Evidence for a Satellite of the Trojan Asteroid (911) Agamemnon
• Binary Candidates in the Jovian Trojan and Hilda Populations from NEOWISE Lightcurves
• A celestial gamma-ray foreground due to the albedo of small solar system bodies and a remote probe of the interstellar cosmic ray spectrum
• Colors of Trans-Neptunian Contact Binaries
• Transformation of Trojans into Quasi-Satellites During Planetary Migration and Their Subsequent Close-Encounters with the Host Planet
• Extreme asteroids in the Pan-STARRS 1 Survey
• Orbital Stability Close to Asteroid 624 Hektor using the Polyhedral Model
• Binary asteroid scattering around white dwarfs
• Close-to-fission dumbbell Jupiter-Trojan (17365) Thymbraeus