Asteroid Radar Database
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277475 (2005 WK4)
Classification: APO [NEO, PHA]
H:20 mag, G:0.15

  MPC page for this object   |  JPL SBDB page for this object   |  NEODyS-2 page for this object   |  ESA SSA page for this object  

History of Radar Detections
Year Month Transmitter Receiver Frequency Obs
2012 Jul Arecibo Arecibo 2380 [A]
2013 Aug Goldstone Goldstone 8560 [G]
2013 Aug Arecibo Arecibo 2380 [A]

Radar-Based Physical Properties
name symbol value units uncertainty reference notes
number of components N 1 - single Based on 2013 Arecibo and Goldstone observations by S. Naidu
morphological type spheroid Based on 2013 Arecibo and Goldstone observations by S. Naidu
spectrum-based or image-based dimensions
maximum range extent Rmax km
minimum range extent Rmin km
maximum Doppler bandwidth Bmax Hz
minimum Doppler bandwidth Bmin Hz
effective diameter Deff km
quality code for size Q
shape-based dimensions
equivalent diameter Dequ km
extent along principal axis x Ex km
extent along principal axis y Ey km
extent along principal axis z Ez km
DEEVE extent along x Dx km
DEEVE extent along y Dy km
DEEVE extent along z Dz km
surface area A km2
volume V km3
spin period Pspin h
spin rate ω deg/day
YORP acceleration ω̇ deg/day2
spin axis ecliptic longitude λ deg
spin axis ecliptic latitude β deg
radar cross-section OC σOC km2
radar cross-section SC σSC km2
radar cross-section σT km2
projected area Aproj km2
radar albedo OC σ̂OC
radar albedo SC σ̂SC
radar albedo σ̂T
circular polarization ratio μC

Orbital Elements at Epoch 2021-07-05 00:00 TT from MPO527904 (heliocentric ecliptic J2000)
Element Value Units
e 0.2372956
a 1.010629 AU
i 9.84365 deg
om 138.12785 deg
w 74.0914 deg
ma 359.1445 deg
n 0.97009992 deg/d

Link to complete orbital information at Minor Planet Center

Earth Close-Approach Data (+/- 10 years)
date nominal distance RTT SNR/run at Arecibo
2012-08-09 00:36:00 0.12829 128.0 4.0
2013-08-09 05:02:00 0.02071 20.7 2128.6
2014-08-12 11:27:00 0.07204 71.9 30.1
2015-08-16 12:01:00 0.16875 168.4 1.6
2016-08-19 17:55:00 0.26469 264.2 0.3
2017-08-24 00:53:00 0.36096 360.2 0.1
2018-08-28 11:40:00 0.45637 455.5 0.1

Link to complete Close-Approach Data on SBDB at JPL