Asteroids with Satellites Database--Johnston's Archive

(31) Euphrosyne

compiled by Wm. Robert Johnston
last updated 27 May 2019

--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: 3.1554023036 AU
orbital period P: 5.6050837663 yr
(= 2047.2955113 d)
eccentricity e: 0.220857025
perihelion distance q: 2.458509538 AU
aphelion distance Q: 3.852295069 AU
inclination i: 26.3033445°
argument of perihelion ω: 61.470392°
ascending node Ω: 31.1185729°
mean anomaly M: 87.1671452°
perihelion passage TP: 2017 Dec 17.286374
Epoch: 2019 Apr 27
data arc: 1860-2018 (2068 obs.)
Earth MOID: 1.56992 AU
Jupiter Tisserand invariant TJ: 3.011


orbital data, secondary:
semimajor axis as: 677 km [V19c]
separation/primary radius as/rp:5.1 [*D]
separation/Hill radius as/rH:0.016 [*D]
orbital period Ps: 1.2 d [V19c]
eccentricity es: ?
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 6.74 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 267.08 ± 2.61 km [JPL]
geometric albedo: 0.053 ± 0.006 [JPL]
color index U-B: 0.317 [JPL]
color index B-V: 0.687 [JPL]
taxonomic type: Cb (SMASSII) [JPL]
C (Tholen) [JPL]
mass m: ?
density ρ: 1 g/cm3[]
Hill radius rH: 44000 km [*D]

other data, primary:
diameter dp: 267.08 ± 2.61 km [JPL]
rotation period RPp: 5.53 h [JPL]
amplitude in mag., rotational ΔM: ?
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: 6.7 ± 2.4 km [*D]
diameter ratio ds/dp: 0.025 ± 0.009 [*D]
component mag. difference ΔM: 8 ± 0.8 [V19c]
rotation period RPs: ?

-- (31) Euphrosyne --discovery and notes:

Primary discovered 1854 Sep 01 from Washington, USA by J. Ferguson. Alternate designation(s): A907 GP, A918 GB. Permanent number assigned 1854.

Named 1854.

Companion discovered 2019 Mar 15 by P. Vernazza, B. Carry, F. Vachier, J. Hanus, J. Berthier, B. Yang, F. Marchis, HARISSA team using adaptive optics telescope observations from Very Large Telescope, ESO, Cerro Paranal, Chile. Announced 2019 May 17 [V19c].

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2019 by Wm. Robert Johnston.
Last modified 27 May 2019.
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