Summary for : (101955) Bennu

DynT.TT.BT T.L B T.DDensity (g/cm^3)Δρ/ρDiameter (km)ΔD/DMass (kg)ΔM/MRefAvg.M
APO--- | -B1.19 ± 0.00   (A)0 %0.5 ± 0.00.0 %7.33e+10 ± 9.00e+070 %SEVM
APO--- | -B1.19 ± 0.00   (A)0 %0.5 ± 0.00.0 %7.33e+10 ± 9.00e+070 %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
(101955) Bennu0.49 ± 0.000.0 % FlyBy2019D109 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 = (0.5 ± 0.00) km   (ΔD/D = 0%, SNR = 3062.87) Derived bulk density ρ = (1.19 ± 0.00) g/cm3   (Δρ/ρ = 0%, SNR = 636.6)


References
D109(2019):Lauretta, D. S., DellaGiustina, D. N., Bennett, C. A., et al. (2019). The unexpected surface of asteroid (101955) Bennu. Nature, 568(7750), 55–60. https://doi.org/10.1038/s41586-019-1033-6

Mass estimates

DesignationMass / Err (kg)ΔM/MMethodYearRefNχ2Use
(101955) Bennu7.33e+10 ± 9.00e+070 %FlyBy 2019M1340.00 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 = (7.329 ± 0.009) × 1010 kg   (ΔM/M = 0%, SNR = 814.3) Derived bulk density ρ = (1.19 ± 0.00) g/cm3   (Δρ/ρ = 0%, SNR = 636.6)


References
M134(2019):Lauretta, D. S., DellaGiustina, D. N., Bennett, C. A., et al. (2019). The unexpected surface of asteroid (101955) Bennu. Nature, 568(7750), 55–60. https://doi.org/10.1038/s41586-019-1033-6