Asteroids with Satellites Database--Johnston's Archive

(617) Patroclus and Menoetius

compiled by Wm. Robert Johnston
last updated 9 October 2021

--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: Jupiter trojan asteroid, L5


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 5.21255213 AU
orbital period P: 11.90101 yr
(= 4346.84389 d)
eccentricity e: 0.13954003
perihelion distance q: 4.48519247 AU
aphelion distance Q: 5.93991181 AU
inclination i: 22.05788892°
argument of perihelion ω: 307.9633711°
ascending node Ω: 44.3502185°
mean anomaly M: 269.745164°
perihelion passage TP: 2024 Jun 24.78800
Epoch: 2021 Jul 01
data arc: 2013-2021 (2141 obs.)
Earth MOID: 3.53199 AU
Jupiter Tisserand invariant TJ: 2.835


orbital data, secondary:
binary dynamical type:O [P07f]
semimajor axis as: 695 ± 10 km [B20g]
separation/primary radius as/rp:11.0 [*D]
separation/Hill radius as/rH:0.017 [*D]
orbital period Ps: 4.28276 ± 0.000005 d [B20g]
eccentricity es: 0.02 ± 0.02 [M06b]
normalized ang. mom. αL: 2.05 [P07f]

other data, system (combined):
absolute mag. H: 8.23 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 168.8 ± 2.6 km [B20g]
geometric albedo: 0.045 ± 0.009 [M10b]
color index U-B: 0.215 [T95a]
color index B-V: 0.677 [T95a]
taxonomic type: P (Tholen) [JPL]
mass m: 1.36x1018 ± 1.1x1017 kg [M06b]
density ρ: 0.81 ± 0.16 g/cm3[B20g]
Hill radius rH: 41000 km [*D]

other data, primary:
diameter dp: 126.6 ± 2 km [*D]
dimensions :130.8 x 126.2 x 122.8km [B20g]
axial ratios a/b, b/c:1.036, 1.028 [*D]
rotation period RPp: 102.78624 ± 0.00015 h [B20g]
amplitude in mag., rotational ΔM: 0.07 [W21b]
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: 111.8 ± 1.7 km [*D]
dimensions :117.1 x 110.8 x 107.8km [B20g]
axial ratios a/b, b/c:1.057;1.028 [*D]
diameter ratio ds/dp: 0.884 ± 0.034 [B20g]
component mag. difference ΔM: 0.27 ± 0.084 [*D]
rotation period RPs: ?

-- (617) Patroclus and Menoetius --discovery and notes:

Primary discovered 1906 Oct 17 from Heidelberg, Germany by A. Kopff. Alternate designation(s): 1906 VY, 1941 XC, 1962 NB. Permanent number assigned 1907 Nov .

Named 1907 for the Greek mythological character [AN04187].

Companion discovered 2001 Sep 22 by W. J. Merline, L. M. Close, N. Siegler, D. Potter, C. R. Chapman, C. Dumas, F. Menard, and D. C. Slater using adaptive optics telescope observations from Gemini North Telescope, Mauna Kea, Hawaii, USA. Announced 2001 Oct 29 [M01a]. Provisional designation S/2001 (617) 1. Permanent designation I Menoetius, assigned 2006 Feb 02; named for the Greek mythological character [G06b].

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2001-2014, 2021 by Wm. Robert Johnston.
Last modified 9 October 2021.
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