Summary for : (162173) Ryugu

DynT.TT.BT T.L B T.DDensity (g/cm^3)Δρ/ρDiameter (km)ΔD/DMass (kg)ΔM/MRefAvg.M
APO-Cb- | --1.19 ± 0.02   (A)2 %0.9 ± 0.00.4 %4.50e+11 ± 6.00e+091 %SEVM
APO-Cb- | --1.19 ± 0.02   (A)2 %0.9 ± 0.00.4 %4.50e+11 ± 6.00e+091 %Sw.avg

Average asteroid densities (g/cm^3):
C = 1.3 ± 0.6, B = 2.4 ± 0.5, S = 2.7 ± 0.5, M = 3.5 ± 1.0, P = 2.8 ± 1.6, X = 1.9 ± 0.8, Xc = 4.9 ± 0.9, Xk = 4.2 ± 0.7 (Ref)

Additional resources:
3D Model | JPL New Horizons | Minor Planet Center | Wikipedia (these auto-generated links might not work)

Note: The density estimates have been ranked from (A) to (E), corresponding to the relative error: (B) less than 20%, (C) between 20 and 50%, (D) between 50 and 100%, and (E) more than 100%. (A) stands for (presumably) reliable estimates (accuracy better than 20%), based on more than 5 mass estimates and 5 diameter estimates, or a spacecraft encounter. Apparently unrealistic densities (ρ > 8) are tagged with (X).

EVM: average by using the Expected Value Method (Ref). w.avg: weighted average (with w = 1/err^2).

T.T: Tholen Tax Class. T.B: Bus & Binzel Tax Class. T T.L: S3OS2 Lazarro (Tholen) Tax Class. T.L B: S3OS2 Lazarro (Bus & Binzel) Tax Class. T.D: DeMeo Tax Class.

Ref: S = SiMDA, C = Carry (2012)

Diameter estimates

DesignationDiameter / Err (km)ΔD/DMethodYearRefNχ2Use
(162173) Ryugu0.90 ± 0.000.4 % FlyBy2019D110 0.00 1

Notes (N):
1: This estimate is discarded for the average diameter (and derived density) calculation in Carry (2012).
2: This estimate is discarded for the average diameter (and derived density) calculation in SiMDA (catalog).

FlyBy : Images from spacecraft encounter.


EVM diam. average D = (0.9 ± 0.00) km   (ΔD/D = 0%, SNR = 224.08) Derived bulk density ρ = (1.19 ± 0.02) g/cm3   (Δρ/ρ = 2%, SNR = 52.9)


References
D110(2019):Watanabe, S.; Hirabayashi, M.; Hirata, N.; et al. (2019). High Porosity Nature of the Top-Shape C-Type Asteroid 162173 Ryugu as Observed by Hayabusa2. Bibcode: https://ui.adsabs.harvard.edu/abs/2019LPI....50.1265W/abstract

Mass estimates

DesignationMass / Err (kg)ΔM/MMethodYearRefNχ2Use
(162173) Ryugu4.50e+11 ± 6.00e+091 %FlyBy 2019M1350.00 1

Notes (N):
1: This estimate is discarded for the average mass (and derived density) calculation in Carry (2012).
2: This estimate is discarded for the average mass (and derived density) calculation in SiMDA (catalog).
3: This estimate is an average of individual solutions listed before under the same reference (e.g. M125).

FlyBy : Spacecraft radio experiment (ranging etc. from flyby, orbiter or lander).


EVM mass average M = (4.500 ± 0.060) × 1011 kg   (ΔM/M = 1%, SNR = 75.0) Derived bulk density ρ = (1.19 ± 0.02) g/cm3   (Δρ/ρ = 2%, SNR = 52.9)


References
M135(2019):Watanabe, S.; Hirabayashi, M.; Hirata, N.; et al. (2019). High Porosity Nature of the Top-Shape C-Type Asteroid 162173 Ryugu as Observed by Hayabusa2. Bibcode: https://ui.adsabs.harvard.edu/abs/2019LPI....50.1265W/abstract