(66391) 1999 KW4

compiled by Wm. Robert Johnston
last updated 6 May 2007

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: 0.642295549059111 AU
orbital period P: 0.5148 y (=188.0 d)
eccentricity e: 0.688389989480485
perihelion distance q: 0.200145722798947 AU
aphelion distance Q: 1.08444538 AU
inclination i: 38.8906884652635°
argument of perihelion omega: 192.595712302457°
ascending node OMEGA: 244.933079137627°
mean anomaly M: 214.428755961491°
perihelion passage TP: 2005-11-02.0280564
Epoch: 18 AUG 2005
data arc: 1998-2005 (1687 obs.)

orbital data, secondary:
semimajor axis a: 2.548 ± 0.015 km [O06a]
semimajor axis/primary radius a/Rp: (3.87)
orbital period P: 17.4223 ± 0.036 h [O06a]
eccentricity e: 0.0004 ± 0.0019 [O06a]
inclination i: 156.1 ± 2 to J2000 [O06a]
argument of perihelion omega: 319.7 ± 182 [O06a]
ascending node OMEGA: 105.4 ± 3 [O06a]
perihelion passage TP: MJD 52055.4132 ± 0.88 [O06a]
=26 May 2001 09:55:00.5

other data, primary:
mean diameter: 1.317 ± (0.040) km [O06a]
dimensions: 1.532 km x 1.495 km x 1.347 km ± (0.045 km) [O06a]
absolute magnitude H: 16.38 [JPL]
rotation period: 2.7645 ± 0.0003 h [O06a]
amplitude delta M: 0.13 [H03a]
color index B-V: ?
color index V-R: ?
color index R-I: ?
slope parameter G: (0.15) [a]
geometric albedo: (0.3?)
mass (component): (2.353 ± 0.100)x1012 kg [O06a]
density: (1.97 ± 0.24) g/cm3 [O06a]
type: Q [A3a]; S(IV) [D07a]

other data, secondary:
mean diameter: 0.451 ± 0.027 km [O06a]
dimensions: 0.571 km x 0.463 km x 0.349 km ± (0.030 km) [O06a]
diameter ratio Ds/Dp: (0.342)
component magnitude difference: (2.5)
mass (component): (0.135 ± 0.024)x1012 kg [O06a]
density: (2.81 +0.82/-0.63) g/cm3 [O06a]
rotation period: 17.4 ± 0.1 h [O06a]

--(66391) 1999 KW4--discovery and notes:

Primary discovered 20 May 1999 by the LINEAR program, Lincoln Laboratory ETS, Socorro, New Mexico, USA, but linked to prediscovery observations from 1998.

Companion first suggested by apparent eclipsing binary signal in photometric observations made 19-27 June 2000 by P. Pravec and L. Sarounova at Ondrejov Observatory. The companion was confirmed by radar observations from Arecibo Observatory from 21-23 May 2001 by L. A. M. Benner, S. J. Ostro, J. D. Giorgini, R. F. Jurgens, J. L. Margot, and M. C. Nolan, announced on 23 May 2001.

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

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2001-2006, 2007 by Wm. Robert Johnston.
Last modified 6 May 2007.
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