Asteroid Radar Database
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101955 Bennu (1999 RQ36)
Classification: APO [NEO, PHA]
H:20.9 mag, G:0.15
Wavefront file Reference: 2013Icar..226..629N

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History of Radar Detections
Year Month Transmitter Receiver Frequency Obs
1999 Sep Goldstone Goldstone 8560 [G]
1999 Sep Arecibo Goldstone 2380 [A-G]
2005 Sep Goldstone Goldstone 8560 [G]
2005 Sep Arecibo Arecibo 2380 [A]
2011 Sep Arecibo Arecibo 2380 [A]

Radar-Based Physical Properties
name symbol value units uncertainty reference notes
number of components N 1 - single 2013Icar..226..629N
morphological type spheroid 2013Icar..226..629N
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 492 km 20 2013Icar..226..629N
quality code for size Q
shape-based dimensions
equivalent diameter Dequ 493 km 2013Icar..226..629N
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 0.786 km2 0.04 2013Icar..226..629N
volume V 0.0623 km3 0.006 2013Icar..226..629N
spin period Pspin 4.29746 h 0.002 2013Icar..226..629N
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 0.023 km2 0.006 2013Icar..226..629N For AO at 12.6cm. At Goldstone at 3.5cm 0C=0.034+/-0.012
radar cross-section SC σSC 0.0043 km2 0.001 2013Icar..226..629N For AO at 12.6cm. At Goldstone at 3.5cm SC=0.0068+/-0.0024
radar cross-section σT km2
projected area Aproj km2
radar albedo OC σ̂OC
radar albedo SC σ̂SC
radar albedo σ̂T
circular polarization ratio μC 0.18 0.01 2008Icar..198..294B Date: 1999T
2013Icar..226..629N has muC=0.18+/-0.03 at S band, 0.19+/-0.03 at X band.

Orbital Elements at Epoch 2022-01-21 00:00 TT from MPO449617 (heliocentric ecliptic J2000)
Element Value Units
e 0.2036885
a 1.125886 AU
i 6.03428 deg
om 2.00021 deg
w 66.33281 deg
ma 192.60435 deg
n 0.82501619 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
2017-09-01 22:21:00 0.33607 335.4 0.3
2018-05-15 08:55:00 0.35188 351.2 0.2
2023-08-25 06:51:00 0.49677 495.8 0.1
2024-06-02 04:34:00 0.35981 359.1 0.2
2025-02-25 04:48:00 0.39155 390.8 0.2
2030-06-21 20:22:00 0.34590 345.2 0.3
2031-02-18 09:48:00 0.23149 231.0 1.1

Link to complete Close-Approach Data on SBDB at JPL