Asteroids with Satellites Database--Johnston's Archive

(66391) 1999 KW4

compiled by Wm. Robert Johnston
last updated 11 May 2014
under construction--testing upgrades!

--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: NEA, Aten (PHA)


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 0.642291859 AU
orbital period P: 0.514762413 yr (= 188.0169715 d)
eccentricity e: 0.688460238
perihelion distance q: 0.200099453 AU
aphelion distance Q: 1.084484265 AU
inclination i: 38.8871737°
argument of perihelion ω: 192.6154467°
ascending node Ω: 244.9231238°
mean anomaly M: 221.227725°
perihelion passage TP: 2014 Aug 03.47650
Epoch: 2014 May 23
data arc: 1998-2013 (1772 obs.)
Earth MOID: 0.0132776 AU
Jupiter Tisserand invariant TJ: 8.498


orbital data, secondary:
binary dynamical type:A [P07f]
semimajor axis as: 2.548 ± 0.015 km [O06a]
separation/primary radius as/rp:3.9 [*D]
separation/Hill radius as/rH:0.114 [*D]
orbital period Ps: 0.7259 ± 0.0015 d [O06a]
eccentricity es: 0.0004 ± 0.0019 [O06a]
inclination is:156.1°± 2 [O06a]
ascending node Ωs:105.4°± 3 [O06a]
argument of pericenter ωs:319.7°± 182 [O06a]
pericenter passage TP:2001 May 26.41°± 0.88 []
normalized ang. mom. αL: 1.06 [P07f]

other data, system (combined):
absolute mag. H: 16.5 [MPC]
16.38 [JPL]
slope parameter G: 0.15 [*A]
effective diameter dE: 1.39 km [*D]
geometric albedo: 0.23 [*E]
color index U-B: ?
color index B-V: ?
taxonomic type: S: (SMASSII) [JPL]
mass m: 2.49x1012 ± 5.4x1010 kg [O06a]
density ρ: 1.97 ± 0.24 g/cm3 [O06a]
Hill radius rH: 22 km [*D]

other data, primary:
diameter dp: 1.317 ± 0.04 km [O06a]
dimensions :1.532 x 1.495 x 1.347 km [O06a]
rotation period RPp: 2.7645 ± 0.0003 h [O06a]
amplitude in mag., rotational ΔM: 0.13 [*H03a]
pole direction : ? ; ?


other data, secondary:
diameter ds: 0.451 ± 0.027 km [O06a]
dimensions :0.571x0.463x0.349km [O06a]
axial ratios a/b, b/c:1.23;1.33 [*D]
diameter ratio ds/dp: 0.341 ± 0.025 [*D]
component mag. difference ΔM: 2.5 [*D]
rotation period RPs: 17.4 ± 0.1 h [O06a]

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

Primary discovered 1999 May 20 from Socorro, New Mexico, USA by LINEAR. . Linked to prediscovery observations from 1998 May 29. Permanent number assigned 2003 Sep 10.

Companion discovered 2001 May 21 using R/LC observations. Announced 2001 May 23.

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2001-2007, 2014 by Wm. Robert Johnston.
Last modified 11 May 2014.
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