TY - JOUR
T1 - Arecibo Planetary Radar Observations of Near-Earth Asteroids
T2 - 2017 December–2019 December
AU - Virkki, Anne K.
AU - Marshall, Sean E.
AU - Venditti, Flaviane C.F.
AU - Zambrano-Marín, Luisa F.
AU - Hickson, Dylan C.
AU - McGilvray, Anna
AU - Taylor, Patrick A.
AU - Rivera-Valentín, Edgard G.
AU - Devogèle, Maxime
AU - Díaz, Eframir Franco
AU - Bhiravarasu, Sriram S.
AU - Hernández, Betzaida Aponte
AU - Sánchez-Vahamonde, Carolina Rodriguez
AU - Nolan, Michael C.
AU - Perillat, Phil
AU - Cabrera, Israel
AU - González, Elliot
AU - Padilla, Daniel
AU - Negrón, Victor
AU - Marrero, Juan
AU - Lebrón, Johbany
AU - Bagué, Adrian
AU - Jiménez, Francisco
AU - López-Oquendo, Andy
AU - Repp, Daniel
AU - McGlasson, Riley A.
AU - Presler-Marshall, Brynn
AU - Howell, Ellen S.
AU - Margot, Jean Luc
AU - Desai, Sanjana Prabhu
N1 - Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/9/1
Y1 - 2022/9/1
N2 - We successfully observed 191 near-Earth asteroids using the Arecibo Observatory’s S-band planetary radar system from 2017 December through 2019 December. We present radar cross sections for 167 asteroids; circular-polarization ratios for 112 asteroids based on Doppler-echo-power spectra measurements; and radar albedos, constraints on size and spin periods, and surface-feature and shape evaluation for 37 selected asteroids using delay-Doppler radar images with a range resolution of 75 m or finer. Out of 33 asteroids with an estimated effective diameter of at least 200 m and sufficient image quality to give clues of the shape, at least 4 (∼12%) are binary asteroids, including 1 equal-mass binary asteroid, 2017 YE5, and at least 10 (∼30%) are contact-binary asteroids. For 5 out of 112 asteroids with reliable measurements in both circular polarizations, we measured circular-polarization ratios greater than 1.0, which could indicate that they are E-type asteroids, while the mean and the 1σ standard deviation were 0.37 ± 0.23. Further, we find a mean opposite-sense circular-polarization radar albedo of 0.21 ± 0.11 for 41 asteroids (0.19 ± 0.06 for 11 S-complex asteroids). We identified two asteroids, 2011 WN15 and (505657) 2014 SR339, as possible metal-rich objects based on their unusually high radar albedos, and discuss possible evidence of water ice in 2017 YE5.
AB - We successfully observed 191 near-Earth asteroids using the Arecibo Observatory’s S-band planetary radar system from 2017 December through 2019 December. We present radar cross sections for 167 asteroids; circular-polarization ratios for 112 asteroids based on Doppler-echo-power spectra measurements; and radar albedos, constraints on size and spin periods, and surface-feature and shape evaluation for 37 selected asteroids using delay-Doppler radar images with a range resolution of 75 m or finer. Out of 33 asteroids with an estimated effective diameter of at least 200 m and sufficient image quality to give clues of the shape, at least 4 (∼12%) are binary asteroids, including 1 equal-mass binary asteroid, 2017 YE5, and at least 10 (∼30%) are contact-binary asteroids. For 5 out of 112 asteroids with reliable measurements in both circular polarizations, we measured circular-polarization ratios greater than 1.0, which could indicate that they are E-type asteroids, while the mean and the 1σ standard deviation were 0.37 ± 0.23. Further, we find a mean opposite-sense circular-polarization radar albedo of 0.21 ± 0.11 for 41 asteroids (0.19 ± 0.06 for 11 S-complex asteroids). We identified two asteroids, 2011 WN15 and (505657) 2014 SR339, as possible metal-rich objects based on their unusually high radar albedos, and discuss possible evidence of water ice in 2017 YE5.
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U2 - 10.3847/PSJ/ac8b72
DO - 10.3847/PSJ/ac8b72
M3 - Article
AN - SCOPUS:85142038836
SN - 2632-3338
VL - 3
JO - Planetary Science Journal
JF - Planetary Science Journal
IS - 9
M1 - 222
ER -