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Table 8 Properties of Ryugu, covered and discussed in the text

From: Asteroid Ryugu before the Hayabusa2 encounter

Global properties
 Measured Eccentricity 0.190208  
Semi-major axis 1.189555 AU
Inclination 5.883556 °
Period 473.8878 Days
Perihelion 0.963292 AU
Aphelion 1.415819 AU
Rotation period 7.6326 h
Pole direction in ecliptic coordinates (lambda, beta) (310–340, − 40 ± 15) °
Shape Almost spherical  
Volume-equivalent diameter 850–880 m
Phase function (Lommel-Seeliger model) see Table 2  
Geometric and bond albedos see Table 3  
Spectral type C-type, see also Table 4  
 Derived Composition (meteorite spectral counterpart) heated CM, CM2, or CI  
 Predicted Satellite no  
Dust around Ryugu no or little  
Boulders: power law exponent of cumulative SFD − 3  
Crater density more than Itokawa, less than Toutatis  
Surface roughness at meter scales like Eros and Itokawa  
Origin Originated in the inner main asteroid belt, between ~ 2.1 and 2.5 AU, and reached the ν6 by inward Yarkovsky drift  
Regolith thermophysical properties
 Measured Thermal inertia 150–300, typically 200 J m−2 s−1/2 K−1
Maximum surface temperature 320–375 K
Roughness (the rms of surface slopes) < 0.1  
 Derived Regolith thermal conductivity 0.020–0.108, most likely 0.042 W m−1 K−1
Typical particle size in diameter 3–30 most likely 6–10 (2.2–5 by Gundlach and Blum 2013 model) mm
 Predicted Regolith heat capacity at 300 K 758 J kg−1 K−1
Regolith emissivity 0.9  
Regolith thermal albedo 0.019  
Regolith bulk density 1100–1500 kg m−3
Regolith mechanical properties
 Predicted Regolith porosity ~ 0.4–0.5  
Regolith cohesion 100 Pa
Regolith angle of friction 33 °
Regolith tensile strength < 1000 Pa
Inter-grain friction angle 40–50 °
Regolith bearing strength < a few 1000 Pa
Compressive strength of rock 15–30 MPa
Tensile strength of rock < 1 MPa
Presence of ponds Possible, there are compositions being expected to be significantly different from that of the bulk asteroid