1998 WW31 and S/2000 (1998 WW31) 1

compiled by Wm. Robert Johnston
last updated 1 March 2006

Orbital elements and other data (Assumed or derived values in parenthesis, my estimates in italics and parenthesis. Source identifications in brackets, see this link for sources):

orbital data, primary (osculating elements) [JPL]:
semimajor axis a: 44.5756757713217 AU
orbital period P: 297.6152 y (=108706 d)
eccentricity e: 0.0857860293266722
perihelion distance q: 40.7517055423468 AU
aphelion distance Q: 48.399646 AU
inclination i: 6.80832424911238°
argument of perihelion omega: 50.042473459635°
ascending node OMEGA: 237.10314722883°
mean anomaly M: 125.053794464°
perihelion passage TP: 1901-09-12.3289346
Epoch: 30 JAN 2005
data arc: 1998-2001 (26 obs.)

orbital data, secondary:
semimajor axis a: 22300 ± 800 km [V02a]
semimajor axis/primary radius a/Rp: (170)
orbital period P: 574 ± 10 d [V02a]
eccentricity e: 0.817 ± 0.05 [V02a]
periapse distance q: (4100 ± 1200 km)
inclination i: 41.7° ± 7° [V02a]
periapse longitude omega: 235.8° ± 7° [V02a]
node longitude OMEGA: 94.3° ± 8° [V02a]
mean anomaly M: 43.4° ± 4° [V02a]
Epoch: JD 2452300.5

other data, primary:
diameter: 133 ± 15 km [V02a]
absolute magnitude H: 6.05 [JPL]
rotation period: ?
amplitude delta M: ?
color index B-V: ?
color index V-R: ?
color index R-I: ?
color index R-J: 1.49 ± 0.21 [T03a]
color index J-H: 0.34 ± 0.23 [T03a]
color index H-K: -0.32 ± 0.38 [T03a]
slope parameter G: (0.15) [a]
geometric albedo: 0.07 ± 0.02 [V02a]
mass (system): 1.7x1018 kg [A3a]
density: (1.5 g/cm3) [a]
type: ?

other data, secondary:
diameter: 110 ± 12 km [V02a]
diameter ratio Ds/Dp: 0.83 [V02a]
component magnitude difference: 0.4 [V02a]
color index R-J: 0.98 ± 0.21 [T03a]
color index J-H: 1.13 ± 0.23 [T03a]
color index H-K: -0.24 ± 0.38 [T03a]
rotation period: ?

--1998 WW31--discovery and notes:

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

Companion discovered 22 December 2000 by Christian Veillet, Joshua Shapiro, and Alain Doressoundiram from the CFHT; announced 16 April 2001. 1998 WW31 is a Kupier Belt or trans-Neptunian object, and the first of this class found to have a satellite.

See more information and links at Asteroid/Comet Connection Catchall Catalog page

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2001-2005, 2006 by Wm. Robert Johnston.
Last modified 1 March 2006.
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