Asteroids with Satellites Database--Johnston's Archive

1998 WW31 and S/2000 (1998 WW31) 1

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: TNO, Cubewano


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 44.4317 AU
orbital period P: 296.169 yr
(= 108177.7 d)
eccentricity e: 0.09103
perihelion distance q: 40.3869 AU
aphelion distance Q: 48.4764 AU
inclination i: 6.82399°
argument of perihelion ω: 50.0586°
ascending node Ω: 237.1556°
mean anomaly M: 141.8396°
perihelion passage TP: 1902 Aug 17.1
Epoch: 2019 Apr 27
data arc: 1998-2011 (32 obs.)
Earth MOID: 39.3742 AU
Jupiter Tisserand invariant TJ: 5.896
Neptune Tisserand invariant TN:3.081 [*D]


orbital data, secondary:
semimajor axis as: 22617 ± 42 km [G19b]
separation/primary radius as/rp:310 [*D]
separation/Hill radius as/rH:0.049 [*D]
orbital period Ps: 587.27 ± 0.18 d [G19b]
eccentricity es: 0.8193 ± 0.002 [G19b]
inclination is:41.36° ± 0.38° [G19b]
ascending node Ωs:94.58° ± 0.72° [G19b]
argument of pericenter ωs:348.49° ± 0.63° [G19b]
mean anomaly M:30.83° ± 0.34° [G19b]
Epoch:2002 Jan 25.5
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 6.7 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 192 km [*D]
geometric albedo: 0.054 ± 0.005 [V02a]
color index U-B: ?
color index B-V: ?
color index R-J:1.49 ± 0.21 [T03a]
color index J-H:0.34 ± 0.23 [T03a]
taxonomic type: ?
mass m: 2.66x1018 ± 1.5x1016 kg [G19b]
density ρ: (1 g/cm3) [*A]
Hill radius rH: 460000 km [*D]

other data, primary:
diameter dp: 148 km [V02a]
rotation period RPp: ?
amplitude in mag., rotational ΔM: ?
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: 123 km [V02a]
diameter ratio ds/dp: 0.833 [V02a]
component mag. difference ΔM: 0.4 [*D]
rotation period RPs: ?

-- 1998 WW31 and S/2000 (1998 WW31) 1 --discovery and notes:

Primary discovered 1998 Nov 18 from Kitt Peak Observatory, Arizona, USA by M. W. Buie.

Companion discovered 2000 Dec 22 by C. Veillet, A. Doressoudiram, and J. Shapiro using imaging observations from CFHT Telescope, Mauna Kea, Hawaii, USA. Announced 2001 Apr 16 [V01a]. Provisional designation S/2000 (1998 WW31) 1.

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2001-2015, 2019 by Wm. Robert Johnston.
Last modified 27 May 2019.
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