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 - Funding Information:
Part of the data utilized in this publication were obtained and made available by the MIT-Hawaii Near-Earth Object Spectroscopic Survey (MITHNEOS). The IRTF is operated by the University of Hawaii under cooperative agreement No. NCC 5-538 with the NASA Office of Space Science, Planetary Astronomy Program. The MITHNEOS is supported by NASA grant 09-NEOO009-0001 and by the NSF under grant Nos. 0506716 and 0907766. This work also uses data obtained from the Asteroid Lightcurve Data Exchange Format (ALCDEF) database, which is supported by funding from NASA grant 80NSSC18K0851, and made use of NASAʼs Astrophysics Data System and the Jet Propulsion Laboratory’s Small-Body Database. A.V. acknowledges funding from the Academy of Finland grants 1325805 and 1345115 for a part of the work. S. M., F.V., and D.H. acknowledge funding from the Preeminent Postdoctoral Program of the University of Central Florida. R. M., B.P., and D.R. were supported by the Arecibo Observatory Research Experience for Undergraduates program, National Science Foundation grant 1559849.
Funding Information:
The authors are sincerely grateful for the Arecibo Observatory’s telescope operations, electronics, and maintenance teams for making these observations possible. These Arecibo planetary radar observations were fully supported by the National Aeronautics and Space Administration’s (NASAʼs) Near-Earth Object Observations program through grant Nos. 80NSSC18K1098 and 80NSSC19K0523 awarded to the University of Central Florida (UCF) and NNX13AQ46G awarded to Universities Space Research Association (USRA). The Arecibo Observatory is a facility of the National Science Foundation (NSF) operated under cooperative agreement by UCF, Yang Enterprises, Inc., and Universidad Ana G. Méndez.
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 -