2011/08/08 by S. D. Wolters, Wolters, Stephen D., B. Rozitis +13 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #High-pressure geophysics and materials #Planetary Science and Exploration
paper · pdf · doi:10.48550/arxiv.1108.1831
openalex publication_date 2011/08/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Asteroid (175706) 1996 FG3 is a binary asteroid and the baseline target for the proposed MarcoPolo-R sample-return mission. We present thermal IR photometry obtained with the ESO VLT+VISIR together with optical photometry obtained with the ESO NTT+EFOSC2 . An absolute visual magnitude HV = 17.833 ± 0.024 and phase parameter G = -0.041 ± 0.005 is derived. The Near-Earth Asteroid Thermal Model (NEATM) has been fitted to the measured fluxes to derive a geometric visual albedo pv = 0.046 ± 0.014, effective diameter at the observed aspect Deff = 1.68 ± 0.25 km, and beaming parameter η = 1.15 for phase angle α = 11.7°. The Advanced Thermophysical Model (ATPM) has been fitted to the measured fluxes to derive a more accurate effective diameter Deff = 1.71 ± 0.07 km and albedo pv = 0.044 ± 0.004. Based on the ATPM results, assuming the same albedo for primary and secondary, we derive a primary mean spherical diameter Dp = (1.69 +0.18/-0.12) km, secondary diameter Ds = 0.51 ± 0.03 km, and a secondary orbital semi-major axis a = (2.8 +1.7/-0.7) km. A low surface thermal inertia Γ = 120 ± 50 J m-2 s-1/2 K-1 was also derived, suggesting a dusty surface and raising questions as to the binary formation mechanism of this asteroid. These physical properties are used to predict a Yarkovsky drift in semi-major axis of (-60 +31/-45) m yr-1.