Asteroids with Satellites Database--Johnston's Archive

(113) Amalthea and S/2017 (113) 1

compiled by Wm. Robert Johnston
last updated 16 July 2017

--Orbital and physical data--

(See this page for definitions of quantities; source codes in brackets, see this link for full references; *A, *D, and *E indicate assumed, derived, and estimated values, respectively.)

dynamical type, primary: main belt asteroid


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 2.3761084474 AU
orbital period P: yr
(= 1337.8204007 d)
eccentricity e: 0.086868676
perihelion distance q: 2.169699052 AU
aphelion distance Q: 2.5825178427 AU
inclination i: 5.042123°
argument of perihelion ω: 79.121877°
ascending node Ω: 123.48218°
mean anomaly M: 334.138913°
perihelion passage TP: 2017 Dec 09.10414
Epoch: 2017 Sep 04
data arc: 1871-2017 (2431 obs.)
Earth MOID: 1.17465 AU
Jupiter Tisserand invariant TJ: 3.531


orbital data, secondary:
semimajor axis as: ?
orbital period Ps: ?
eccentricity es: ?
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 8.74 [MPC]
slope parameter G: 0.35 [JPL]
effective diameter dE: 50.14 ± 1.26 km [M11b]
geometric albedo: 0.224 ± 0.018 [M11b]
color index U-B: 0.521 [JPL]
color index B-V: 0.925 [JPL]
taxonomic type: S (SMASSII) [JPL]
S (Tholen) [JPL]
mass m: ?
density ρ: (1.6 g/cm3) [*A]
Hill radius rH: 8500 km [*E]

other data, primary:
diameter dp: 50.14 ± 1.26 km [M11b]
rotation period RPp: 9.95 h [JPL]
amplitude in mag., rotational ΔM: ?
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: 5 km [*E]
diameter ratio ds/dp: ?
component mag. difference ΔM: ?
rotation period RPs: ?

-- (113) Amalthea and S/2017 (113) 1 --discovery and notes:

Primary discovered 1871 Mar 12 from Dusseldorf by R. Luther. Alternate designation(s): 1931 TN3, 1951 CY. Permanent number assigned 1871.

Named 1871 Apr for the Greek mythological character.

Companion discovered 2017 Mar 14 by P. Maley, R. Campbell, D. Eisfeldt, S. Insana, T. Blank, W. Thomas, S. Dean using stellar occultation observations from Phoenix, Arizona; Waco, Texas; Clifton, Texas. Announced 2017 Jul 12. Provisional designation S/2017 (113) 1.

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2017 by Wm. Robert Johnston.
Last modified 16 July 2017.
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