Summary for : (375) Ursula

DynT.TT.BT T.L B T.DDensity (g/cm^3)Δρ/ρDiameter (km)ΔD/DMass (kg)ΔM/MRefAvg.M
MBACXc- | --1.84 ± 1.14   (D)62 %191.9 ± 3.82.0 %6.79e+18 ± 4.21e+1862 %SEVM
MBACXc- | --2.18 ± 1.03   (C)47 %193.1 ± 6.83.5 %8.21e+18 ± 3.79e+1846 %Sw.avg
MBAXc2.29 ± 1.43   (D)62 %191.7 ± 4.02.1 %8.45e+18 ± 5.26e+1862 %C?

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
(375) Ursula183.47 ± 10.465.7 % Occ2011D952 0.64 1
(375) Ursula193.63 ± 2.521.3 % STM2011D83 0.49 2

plot, average diameter and derived density

All

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).

Occ : Stellar occultation. STM : Standard Thermal Model.


EVM diam. average D = (191.9 ± 3.85) km   (ΔD/D = 2%, SNR = 49.89) Derived bulk density ρ = (1.84 ± 1.14) g/cm3   (Δρ/ρ = 62%, SNR = 1.6)


References
D83(2011):Usui, F., Kuroda, D., Müller, T.G., Hasegawa, S., Ishiguro, M., Ootsubo, T., Ishihara, D., Kataza, H., Takita, S., Oyabu, S., Ueno, M., Matsuhara, H., Onaka, T., 2011. Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey. Publications of the Astronomical Society of Japan 63, 1117–1138.
D95(2011):Dunham, D.W., Herald, D., Frappa, E., Hayamizu, T., Talbot, J., Timerson, B., 2011. Asteroid Occultations. NASA Planetary Data System. EAR-A-3-RDR-OCCULTATIONS-V9.0.

Mass estimates

DesignationMass / Err (kg)ΔM/MMethodYearRefNχ2Use
(375) Ursula2.64e+18 ± 5.67e+18215 %Deflec 2011M9720.54 1
(375) Ursula7.14e+18 ± 3.93e+1855 %Deflec 2011M9720.01 2
(375) Ursula7.44e+18 ± 3.89e+1852 %Deflec 2011M9720.03 3
(375) Ursula1.88e+19 ± 6.40e+1834 %Ephem 2011M10023.52 4
(375) Ursula1.17e+19 ± 1.19e+1810 %OrbFitN 2014M12317.22 5
(375) Ursula3.13e+18 ± 1.44e+1846 %Ephem 2019M1266.47 6

plot, average mass and derived density

All

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).

Deflec : Orbital deflection (close encounter) of one or several test asteroids (classical LSQ). Ephem : Planetary ephemeris solution. OrbFitN : Simultaneous multi-asteroid astrometric orbit solution (similar to 'Ephem').


EVM mass average M = (6.792 ± 4.209) × 1018 kg   (ΔM/M = 62%, SNR = 1.6) Derived bulk density ρ = (1.84 ± 1.14) g/cm3   (Δρ/ρ = 62%, SNR = 1.6)


References
M97(2011):Zielenbach, W., 2011. Mass Determination Studies of 104 Large Asteroids. Astronomical Journal 142, 120–128.
M100(2011):Fienga, A., Kuchynka, P., Laskar, J., Manche, H., Gastineau, M., 2011. Asteroid mass determinations with INPOP planetary ephemerides. EPSC-DPS Joint Meeting 2011 , 1879.
M123(2014):Goffin, E., 2014. Astrometric asteroid masses: a simultaneous determination. Astronomy & Astrophysics, Volume 565, id.A56, 8 pp.
M126(2019):Fienga, A., et. al, 2019. INPOP19a planetary ephemeris. Notes Scientifiques et Techniques de l'Institut de mécanique céleste,