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Summary for : (65) Cybele

Dyn	T.T	T.B	T T.L B	T.D	Density (g/cm^3)	Δρ/ρ	Diameter (km)	ΔD/D	Mass (kg)	ΔM/M	Ref	Avg.M
MBA	P	Xc	C \| C	Xk	1.69 ± 0.60 (C)	36 %	259.8 ± 25.8	9.9 %	1.55e+19 ± 3.01e+18	19 %	S	EVM
MBA	P	Xc	C \| C	Xk	1.60 ± 0.51 (C)	32 %	262.6 ± 16.3	6.2 %	1.52e+19 ± 3.92e+18	26 %	S	w.avg
MBA	Xk				1.70 ± 0.52 (C)	31 %	248.3 ± 17.6	7.1 %	1.36e+19 ± 3.10e+18	23 %	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

Designation	Diameter / Err (km)	ΔD/D	Method	Year	Ref	N	χ²	Use
(65) Cybele	237.25 ± 4.19	1.8 %	STM	2004	D93		28.87	1
(65) Cybele	272.70 ± 10.89	4.0 %	TPM	2004	D12		1.41	2
(65) Cybele	231.87 ± 9.44	4.1 %	STM	2010	D64		8.73	3
(65) Cybele	272.01 ± 11.15	4.1 %	NEATM	2010	D64		1.21	4
(65) Cybele	300.54 ± 4.82	1.6 %	STM	2011	D83	12	71.57	5

plot, average diameter and derived density

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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).

NEATM : Near-Earth Asteroid Thermal Model. STM : Standard Thermal Model. TPM : Thermophysical Model.

EVM diam. average D = (259.8 ± 25.82) km (ΔD/D = 10%, SNR = 10.06) Derived bulk density ρ = (1.69 ± 0.60) g/cm³ (Δρ/ρ = 36%, SNR = 2.8)

References

D12	(2004):	Müller, T.G., Blommaert, J.A.D.L., 2004. 65 Cybele in the thermal infrared: Multiple observations and thermophysical analysis. Astronomy and Astrophysics 418, 347–356.
D64	(2010):	Ryan, E.L., Woodward, C.E., 2010. Rectified Asteroid Albedos and Diameters from IRAS and MSX Photometry Catalogs. Astronomical Journal 140, 933–943.
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.
D93	(2004):	Tedesco, E.F., Noah, P.V., Noah, M.C., Price, S.D., 2004. IRAS Minor Planet Survey. NASA Planetary Data System. IRAS-A-FPA-3-RDR-IMPS-V6.0.

Mass estimates

Designation	Mass / Err (kg)	ΔM/M	Method	Year	Ref	N	χ²	Use
(65) Cybele	1.15e+19 ± 2.98e+18	26 %	Deflec	2002	M31		1.79	1
(65) Cybele	1.15e+19 ± 2.98e+18	26 %	Deflec	2004	M42		1.79	2
(65) Cybele	1.78e+19 ± 1.21e+18	7 %	Deflec	2008	M72		3.67	3
(65) Cybele	1.04e+19 ± 1.04e+18	10 %	Ephem	2009	M86	2	23.88	4
(65) Cybele	1.43e+19 ± 8.47e+18	59 %	Ephem	2010	M93		0.02	5
(65) Cybele	1.05e+19 ± 1.91e+18	18 %	Deflec	2011	M95	2	6.80	6
(65) Cybele	1.62e+19 ± 3.68e+18	23 %	Deflec	2011	M97		0.04	7
(65) Cybele	1.52e+19 ± 3.46e+18	23 %	Deflec	2011	M97		0.01	8
(65) Cybele	1.52e+19 ± 3.45e+18	23 %	Deflec	2011	M97		0.01	9
(65) Cybele	1.75e+19 ± 1.16e+19	66 %	Deflec	2011	M97		0.03	10
(65) Cybele	1.75e+19 ± 5.17e+18	30 %	Ephem	2011	M100		0.15	11
(65) Cybele	1.77e+19 ± 7.95e+17	4 %	OrbFitN	2014	M123		7.78	12
(65) Cybele	1.38e+19 ± 2.82e+18	20 %	Deflec	2017	M125	2	0.36	13
(65) Cybele	2.15e+19 ± 5.79e+18	27 %	Deflec	2017	M125	2	1.07	14
(65) Cybele	1.69e+19 ± 4.67e+18	28 %	Deflec	2017	M125	2	0.09	15
(65) Cybele	5.03e+19 ± 2.19e+19	44 %	Deflec	2017	M125	2	2.53	16
(65) Cybele	1.60e+19 ± 2.23e+18	14 %	Deflec	2017	M125	3	0.06	17
(65) Cybele	2.01e+19 ± 3.39e+18	17 %	Ephem	2019	M126		1.86	18

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 = (1.548 ± 0.301) × 10¹⁹ kg (ΔM/M = 19%, SNR = 5.1) Derived bulk density ρ = (1.69 ± 0.60) g/cm³ (Δρ/ρ = 36%, SNR = 2.8)

References

M31	(2002):	Chernetenko, Y.A., Kochetova, O.M., 2002. Masses of some large minor planets, in: B. Warmbein (Ed.), Asteroids, Comets, and Meteors: ACM 2002, pp. 437–440.
M42	(2004):	Kochetova, O.M., 2004. Determination of Large Asteroid Masses by the Dynamical Method. Solar System Research 38, 66–75.
M72	(2008):	Baer, J., Milani, A., Chesley, S.R., Matson, R.D., 2008. An Observational Error Model, and Application to Asteroid Mass Determination, in: Bulletin of the American Astronomical Society, p. 493.
M86	(2009):	Folkner, W.M., Williams, J.G., Boggs, D.H., 2009. The planetary and lunar ephemeris de 421. IPN Progress Report 42, 1–34.
M93	(2010):	Fienga, A., Manche, H., Kuchynka, P., Laskar, J., Gastineau, M., 2010. INPOP10a. Scientific Notes.
M95	(2011):	Baer, J., Chesley, S.R., Matson, R.D., 2011. Astrometric Masses of 26 Asteroids and Observations on Asteroid Porosity. Astronomical Journal 141, 143–155.
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.
M125	(2017):	Baer, J., Chesley, S.R., 2017. Simultaneous Mass Determination for Gravitationally Coupled Asteroids. The Astronomical Journal, Volume 154, Issue 2, article id. 76, 11 pp.
M126	(2019):	Fienga, A., et. al, 2019. INPOP19a planetary ephemeris. Notes Scientifiques et Techniques de l'Institut de mécanique céleste,

Size, Mass and Density of Asteroids (SiMDA)

Summary for : (65) Cybele

Diameter estimates

Mass estimates