Minor Planet Radar Database
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99942 Apophis (2004 MN4)
Classification: ATE [NEO, PHA]
H:18.9 mag, G:0.15

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History of Radar Detections
Year Month Transmitter Receiver Frequency Obs
2005 Jan Arecibo Arecibo 2380 [A]
2005 Aug Arecibo Arecibo 2380 [A]
2006 May Arecibo Arecibo 2380 [A]
2012 Dec Goldstone Goldstone 8560 [G]
2013 Feb Arecibo Arecibo 2380 [A]

Radar-Based Physical Properties
name symbol value units uncertainty reference notes
number of components N
morphological type
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 0.1 0.2 2008Icar..198..294B Date: 2006T

Orbital Elements at Epoch 2019-04-27 00:00 TT from MPO469004 (heliocentric ecliptic J2000)
Element Value Units
e 0.1914656
a 0.9225196 AU
i 3.33688 deg
om 204.05485 deg
w 126.68109 deg
ma 163.22254 deg
n 1.112348 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
2013-01-09 11:43:00 0.09666 96.5 33.2
2013-07-08 07:36:00 0.24331 242.8 1.3
2014-04-04 12:22:00 0.37369 372.9 0.3
2020-01-05 04:06:00 0.44771 446.8 0.2
2020-10-12 08:37:00 0.21628 215.8 2.0
2021-03-06 01:15:00 0.11265 112.4 19.5
2027-12-29 14:23:00 0.29361 293.0 0.7
2028-09-12 04:11:00 0.25657 256.1 1.1
2029-04-13 21:46:00 0.00025 0.3 0.0

Link to complete Close-Approach Data on SBDB at JPL