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Summary for : (13) Egeria

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	G	Ch	- \| -	Ch	1.80 ± 0.94 (D)	52 %	211.2 ± 10.1	4.8 %	8.90e+18 ± 4.45e+18	50 %	S	EVM
MBA	G	Ch	- \| -	Ch	1.49 ± 0.82 (D)	55 %	209.0 ± 6.1	2.9 %	7.15e+18 ± 3.85e+18	54 %	S	w.avg
MBA	Ch				1.70 ± 0.86 (D)	51 %	214.7 ± 11.5	5.4 %	8.82e+18 ± 4.25e+18	48 %	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)

Object is a Gaia target for mass determination !

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	χ²	Use
(13) Egeria	207.63 ± 8.30	4.0 %	STM	2004	D93	0.18	1
(13) Egeria	223.08 ± 3.46	1.6 %	STM	2010	D64	11.79	2
(13) Egeria	226.06 ± 9.49	4.2 %	NEATM	2010	D64	2.45	3
(13) Egeria	203.36 ± 2.56	1.3 %	STM	2011	D83	9.38	4
(13) Egeria	227.00 ± 25.95	11.4 %	NEATM	2011	D72	0.37	5
(13) Egeria	209.00 ± 8.00	3.8 %	ADAM	2017	D100	0.08	6
(13) Egeria	201.00 ± 4.00	2.0 %	ADAM	2017	D100	6.50	7

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).

ADAM : All-Data Asteroid Modeling. NEATM : Near-Earth Asteroid Thermal Model. STM : Standard Thermal Model.

EVM diam. average D = (211.2 ± 10.11) km (ΔD/D = 5%, SNR = 20.90) Derived bulk density ρ = (1.80 ± 0.94) g/cm³ (Δρ/ρ = 52%, SNR = 1.9)

References

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.
D72	(2011):	Masiero, J.R., Mainzer, A.K., Grav, T., Bauer, J.M., Cutri, R.M., Dailey, J., Eisenhardt, P.R.M., McMillan, R.S., Spahr, T.B., Skrutskie, M.F., Tholen, D., Walker, R.G., Wright, E.L., DeBaun, E., Elsbury, D., Gautier, IV, T., Gomillion, S., Wilkins, A., 2011. Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters. Astrophysical Journal 741, 68.
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.
D100	(2017):	Hanuš, J., Viikinkoski, M., Marchis, F., et al., 2017. Volumes and bulk densities of forty asteroids from ADAM shape modeling. Astronomy and Astrophysics 601, A114 (2017). DOI: 10.1051/0004-6361/201629956

Mass estimates

Designation	Mass / Err (kg)	ΔM/M	Method	Year	Ref	N	χ²	Use
(13) Egeria	1.63e+19 (+3.18e+18 / -3.18e+18)	20 % / 20 %	Deflec	2008	M72		5.41	1
(13) Egeria	6.17e+18 (+6.17e+17 / -6.17e+17)	10 % / 10 %	Ephem	2009	M86		19.60	2
(13) Egeria	2.22e+19 (+1.60e+19 / -1.60e+19)	72 % / 72 %	Ephem	2010	M93		0.69	3
(13) Egeria	1.59e+19 (+4.38e+18 / -4.38e+18)	28 % / 28 %	Deflec	2011	M95		2.55	4
(13) Egeria	1.29e+19 (+4.70e+18 / -4.70e+18)	36 % / 36 %	Deflec	2011	M97		0.72	5
(13) Egeria	7.39e+18 (+3.24e+18 / -3.24e+18)	44 % / 44 %	Deflec	2011	M97		0.22	6
(13) Egeria	6.07e+18 (+3.20e+18 / -3.20e+18)	53 % / 53 %	Deflec	2011	M97		0.78	7
(13) Egeria	8.26e+18 (+6.10e+18 / -6.10e+18)	74 % / 74 %	Deflec	2011	M97		0.01	8
(13) Egeria	9.35e+18 (+7.95e+17 / -7.95e+17)	9 % / 9 %	OrbFitN	2014	M123		0.31	9
(13) Egeria	2.25e+19 (+2.05e+19 / -1.59e+19)	91 % / 71 %	Defl-MC	2017	M127	2	0.56	10
(13) Egeria	3.67e+18 (+1.16e+18 / -1.16e+18)	32 % / 32 %	Ephem	2019	M126		20.31	11

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).
4: Values with asymmetric errors are currently just diplayed but disabled (unchecked) for the average calculation.

Defl-MC : Orbital deflection (close encounter) of one or several test asteroids (Markov Chain Monte Carlo, MCMC). 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 = (8.902 ± 4.447) × 10¹⁸ kg (ΔM/M = 50%, SNR = 2.0) Derived bulk density ρ = (1.80 ± 0.94) g/cm³ (Δρ/ρ = 52%, SNR = 1.9)

References

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.
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,
M127	(2017):	Siltala, L., Granvik, M., 2017. Asteroid mass estimation using Markov-chain Monte Carlo. Icarus 297 (November 2017), 149-159. https://doi.org/10.1016/j.icarus.2017.06.028

Size, Mass and Density of Asteroids (SiMDA)

Summary for : (13) Egeria

Diameter estimates

Mass estimates